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Chapter Text

    There wasn't much to say about the way he met him. Sherlock Holmes was not a man characterized by striving to socialize with whatever entity appeared in his path, but the way in which his presence was out of tune with the environment made it impossible for him to notice him without being intrigued.

     He had then been in Brighton for about a week, a seaside town whose attractions drew in countless tourists who flitted day and night along the seafront; and yet he was no less bored than he had been in London. The novelty of the change of scenery had already disappeared, and since he did not have enough money either, it occurred to him to lend his services as a detective despite being on vacation.

     Although nothing but trifles reached his ears, he ended up searching for a pearl necklace. His owner, a wealthy, middle-aged woman, was very insistent despite his advice that it was best to leave it in the hands of the police.

     "It's been almost two weeks and Scotland Yard hasn't even been able to catch the culprit," she replied then, closing the black fan in outrage and slamming it against the coffee table. "I can not keep waiting; I will be leaving this city soon and that necklace is a family heirloom. If you can get it back, I will pay you the amount you want."

     "I don't promise to bring you results, but I'll see what I can find out about it," he agreed, at last, more to get rid of the issue than anything else. He sensed that he would sink deeper into boredom instead of coming out of it with such a job.

     He was only partly right. He didn't come across any hint of anything interesting, beyond the necessary clues; until while he was chatting with a couple of fishermen in the market area, whose establishment was located directly on the beach, he noticed a man who seemed oblivious to everything around him. Leaning against the wooden edge of an empty stall, the light suit he was wearing did not make him look like a nondescript worker, nor did his attitude match that of the visitors who swarmed the other side of the cliffs. He blinked; in short, he didn't believe he had seen him there in previous days.

     "Hey, you're not from here but you're not a tourist either, right?" He approached him with self-confidence as he ended the conversation with the other men and they resumed their tasks.

     The stranger turned his abstracted expression to him. His straight blond hair gleamed over his fine features, but his scarlet eyes were doubtful due to the confusion Sherlock's words must have caused him.

     "It is so," he admitted with some reluctance. He rose to face him on the same level. "Although I think the same could be said of you. You must be the investigator the rumors speak of."

     "Did you overhear my conversation from earlier?" he asked, frowning. A scathing flash crossed the other's gaze.

     "It was not necessary; a single glance was enough to know that you are not a simple foreigner interested in local commerce." His lips curved up and he tilted his head. "It is as obvious as the fact that you came to ask me if I know anything about a certain matter."

     The strangeness he had felt was gone in an instant. An effervescent rush of emotion took its place and made him laugh.

     "I'd say you're more interesting than that topic." He said with a snort and ran his hand across his forehead. He then placed it on his shoulder and asked "What's your name? If you know so much you may already know my name, and it doesn't seem fair to me not to know yours."

     The young man's sight fell on his careless grip and then returned to his face. The smile lingered in his gaze.

     "Call me William," he said and made a gentle denial gesture. "But you are wrong, your name has not reached my ears yet, Mr. Detective."

     His heart pounded; He had the impression of leaving a very long dream behind, the beginning of which he could not remember.

Chapter Text

     He proposed to William, whom he recently met, to go for a walk while he told him about the necklace he was tracking. Despite the suspicious expression he gave him, his blond eyebrow raised, he did not refuse and they climbed the steps towards the crowded boardwalk. The sun was covered by clouds that afternoon, but it was not an impediment to enjoying a day at the beach.

     "I understand the situation," he said, brushing his chin with his fingers in a thoughtful gesture. "Crime has been on the rise lately, hand in hand with poverty."

     "You're not from here but you know a lot, huh?" Sherlock observed from beside him as he struggled to light a match against the sea breeze to smoke a cigarette.

     "I stay in Brighton for one week a month, but I don't think that is important for the case, Mr. Holmes."

     "Dammit!" He exclaimed. The flame went out before he could transfer it to the tobacco. He threw it to the ground and looked at him, frowning, "And stop calling me that, what's all the formality?"

     "You are the one who is too informal" he replied, not changing his manner, and crossed his arms behind his back. "Either way, I think I can help you."

     "Do you already have an idea about the thieves' whereabouts? Because I have one." He chuckled. With every minute he passed with Liam (as he decided to name him in his head), his curiosity grew like foam after a wave slammed against the rocks a few feet away.

     "It's not like it's very difficult to find an object like that in a small city if you ask in the right places" he smiled at him.

     In the slums where London's crowds tried to stay away from, Sherlock found a couple of guys who were trading stolen goods. Pretending to be an interested customer, he managed to rummage through the products and eventually found the damn necklace. The emerald set between the pearls matched the photograph his client had shown him. Stealing it back was not a problem, although there was a detail about the situation that made him uncomfortable.

     "If you were involved in that kind of thing, it wasn't a very good idea for you to help me, you know?" He blurted out by way of a warning the following day. He had proposed to Liam to meet in the same place, on the walk in front of the coast, to reveal the results to him. The truth is that it was more a pretext to see him again; He rarely came across people whose insight equaled his own, and he supposed he was going to regret it if he didn't make at least one attempt to spend time with him.

     "I'm not the only one who knows that address," he excused himself, though he didn't look alarmed at all. "You can imagine that if I was one of those criminals, I would have set you up."

     "Perhaps the trap is yet to come?" He asked with a half-smile, leaning back against the iron railing that overlooked the coast. "Still, I think you deserve half the credit, it would have taken me half a day longer to find it if it weren't for you. Let me buy you lunch."

     "I'm a little busy this afternoon, so I will have to pass this time."

     "Ah, come on, will you go without eating wherever you have to go? It won't take much of your time."

     "If you are so bored, maybe you should look for your next case" Liam pointed out, looking through him with almost terrifying ease. Sherlock quickly overcame his surprise to answer him, but before he opened his mouth, he thought he saw him sigh. "Although I suppose I can afford an hour."

     "You won't regret it."

     He winked at him as he pressed his fist friendly against his arm. Unlike the day before, the sun was now shining brightly over the turbulent ocean. Sherlock, however, was more interested in the way the light penetrated the scarlet stream of those eyes that he could not decipher.

 
     He wasn't sure what led him to give in. William was used to receiving the kindness of people when he offered his help, but in the case of Sherlock Holmes, he felt that there was a noticeable difference. He was a curious man; in addition to being indefatigable whenever he dealt with a particular matter. Although he devoted himself to evade his attempts to meddle in the interstices of the brief personal story he told him, his impudence managed to make him smile more than once during the meal.

     "So you're kind of a counselor," Sherlock said slowly, clasping his hands on the table and resting his face on them. "I guess that explains why you were so willing to help me before, even if you didn't ask me for a single pound."

     "It costs me nothing to share what I know with those who ask or seem to need it," he said, not giving it the slightest importance. "I suppose you understand since you don't seem to dedicate yourself to your trade for the money."
    "And you're not wrong, Liam. As for me, there is no greater pleasure than solving a good mystery. The rest is secondary."

     He kept his eyes on his glittering blue irises. That speech stirred something deep in his consciousness, a breeze through his heart. In the past, William had also taken an interest in things that were beyond his grasp and understanding; And it could even be said that that was why he was in that town now. Mysteries that would be insignificant for Sherlock Holmes.

     "I appreciate the invitation, but I must go now, or else I will be late," he announced later, as he got up.

     "Hey, at least tell me where to find you, we have to repeat this," he asked, pointing the recently lit cigar at him from his place. "Or send me a telegram to the hotel; I've already told you the address."

     "I'll take the second alternative, Mr. Holmes." He mimicked his previous gesture of closing one eye at him and turned toward the door.

     The icy sea in the distance looked less inviting than it had upon entering the restaurant.

Chapter Text

A succession of arches atop the Gothic columns gave the Brighton Aquarium the perspective of expanding into infinite space. It had been built just a few years ago, in 1872, and it was one of the places that his brother had most strongly recommended visiting when he had learned that he would visit the city. The truth is that the idea had emerged in Sherlock's mind only after seeing an advertisement in the morning paper; a small note that had come with a strange piece of news that had caught his attention.

     Behind the thick wall of glass that separated them from the world of the depths, a pair of stingrays crawled lazily across the clear sands. Liam was watching them with apparent self-absorption; but his eyes, once a vibrant red, were so blank and cold that Sherlock hesitated between interrupting his musings and continuing to watch him.

     "You said you had already come once. Maybe we should have gone somewhere else, after all" he commented, leaning over Liam. His partner looked back then; the bluish light of the pool reflected faintly on his profile.

     "It's a pretty rare place, no matter how many times you see it," he said, shaking his head in denial. "Although my little brother did not like it very much when we came. There haven't been that many species then."

     "You don't seem to like it either, and I don't blame you when it comes to these," he pointed to the stingrays continuing their phlegmatic wandering. "They must be the most boring thing you can find around here."

     Neither the huge sharks nor the jellyfish, with their delicate and ghostly forms, made the same impact on him as on the rest of the impressionable onlookers around him. Over the murmurs of admiration and surprise, Sherlock turned over that new piece of information Liam had just given him: he had at least one younger brother to hang out with when he was not preoccupied with unknown matters. He would not have attached such importance to it if it had not been for the fact that he had known him for five days and it was the first time that Liam had mentioned something related to his family; otherwise, he could not outline him with the usual ease. Trying to see under his distant courtesy Sherlock was only getting traces of information and isolated clues.

     However, they had grown to understand each other unusually fast, and engaging in conversations with him was more like wandering through the park with a friend than plunging into unexplored terrain. He didn't want to stop, and time always seemed to run out too soon.

     "A couple of fishermen say they spotted mermaids near here," Sherlock told him when they took a break on the roof to smoke. He brushed the ashes off the balustrade and added "Since crime is on the rise, I was hoping to find something good, but I only found a lot of fantasies."

     "Are mysteries like these beyond your abilities?" A mocking smile creased his lips.

     "No, but if you're interested, you could figure it out. You're incredibly skilled at swimming, aren't you?" Sherlock had deduced that characteristic from his movements as he walked and forgot to mention it to him earlier.

     Wariness took the place of wonder he expected to see on Liam's face. He crossed his arms over the railing instead of answering immediately.

     "You guessed right, although something like that is easy for a detective like you," he acknowledged. "One who also plays the violin and has a habit of using drugs."

     "Ah! How did you know that?" He was prepared for an attack of the same caliber, but it still puzzled and amazed him at the same time that someone was able to read him to that degree. Apart from Mycroft, who was his brother and was unfortunately ahead of him in that regard, he had not had similar experiences.

     "It's too obvious not to notice after having met each other so many times."

     "You really believe you're all that, huh? Cocky little one."

     He laughed and patted Liam's shoulder until he made him laugh too. Silhouetted against the twilight, his laughing face was ethereal and warm, as if the breeze were to carry him along with the sun. Sherlock raised his hand, his fingers about to touch his skin. He didn't know if he intended to hold him back or was simply content to capture the soft touch in his memory. He lowered it before figuring it out.

     "The truth is I don't usually rule out any possibility, however impossible, unless there's evidence involved," Sherlock said to fill the sudden silence, staring out at the ocean. "If mermaids were to exist, maybe some will end up in one of the ponds here. Of course, they would be more entertaining to watch than a stingray vegetate."

     "In that case, if I ever find one, I'll warn them to be careful."
When Liam glanced at him again, he found another unreadable mask over his well-defined features. Focused on whatever was beyond the crimson horizon, he didn't look back at him, but Sherlock still smiled at him.

Chapter Text

"You're leaving in two days?" Sherlock snapped, his voice thick with disappointment. At the time of dropping this announcement, they were in the middle of the West Pier, the western pier whose gigantic iron structure contained a theater and other venues. "I didn't think you would leave town before me."

     "I mentioned that I only stay here one week a month, remember?" Liam indicated. "It was when we first met."

     Sherlock paused, recalling that conversation as if the roar of the ocean contained the words of his new friend. He took his hand out of his trouser pocket and ran it through his black hair in an irrepressible gesture of annoyance.

     "But you didn't say why, may I ask now?"

     "I must go home" he replied, with a fleeting and weak smile, as his eyes flew to the immensity of the sea that opened at his side. "This is not my home, even though it may seem like it."

     He fell silent and resumed his stride shortly after, his brows furrowed; Liam followed without adding anything. He ruminated on the many things he wanted to tell him along with the many others that he perceived; the latter Sherlock felt them float away from him before he could grasp them, and the sensation was beginning to tighten his nerves. He knew perfectly well that Liam was not obliged to give him any explanation; they were nothing short of strangers, despite not feeling that way. The proximity of his farewell tasted more bitter than the coffee without a pinch of sugar that he then ordered in the cafeteria of that picturesque place, and he was overwhelmed with discouragement.

     Liam sipped his tea as if he existed in a different dimension and didn't hear the taut drumming of his fingertips on the tablecloth. Perhaps it was not an absurd idea; It was quite possible that he didn't care in the same way and that Sherlock was fooling around on his own with those unsupported emotions. Maybe he had invented such a connection unconsciously, spurred on by the lack of mental stimuli.

     "I think I should have said it yesterday, in case you had any other plans in mind," Liam began, wrapping his fingers around his cup. "I regret not being able to accompany you for the rest of your stay."

     "It doesn't matter, you don't really owe me anything." He cleared his throat, feeling somewhat uncomfortable at the sincerity of his apology. He looked away and searched for the cigarettes inside his coat. "It's not like I'm going to be here much longer either."

     Liam's lips curved upwards and again his gaze seemed to drift away, lost in an unspeakable point outside the material world. He didn't speak to Sherlock again until they made their way back across the boardwalk, and when he spoke he brought with him an unexpected statement.

     "Sherlock, don't think I don't appreciate the time I spent with you," he said, his face more serious than Sherlock had ever seen him outline. "It was very short, and I would ... I would like to stay, but it is something that is not up to me."

     Aside from the fact that it was the first time Liam had ever called him by his first name, Sherlock couldn't understand the full meaning of the last sentence; However, the helplessness that shone in his eyes took away his desire to press him for answers.

     "This isn't my home either, Liam. Although since I met you it has been tremendously fun, more than if it was" he replied, more gently. "What I mean is that there won't be much difference between being alone here or in London, so I don't care where it will be. But you can write to me, you know? Since you refuse to give me any addresses, you better do so."

     Looking dumbfounded amid the passersby, Liam waited a few seconds and nodded with his eyes closed. Then Sherlock had the feeling that he would say goodbye to him and disappear into the crowd if he didn't stop him, so he rushed to improvise:

     "You have one more day off, right? I'll see you here tomorrow afternoon and make sure you don't waste it."

     "Wanting to monopolize my time is childish of you" he observed wryly, though Sherlock preferred this attitude to his earlier melancholic expression. "I hope you at least pay for the coffee."

     "I'll think about it. This damn city swallows my pounds like water."

That was the arrangement, but when Sherlock crossed the pier the next day he didn't see Liam around any corner. It wouldn't have seemed strange if it weren't for the fact that Liam used to be more punctual than him, and even used to be ahead of the agreed times. He stood a few meters from the theater, from where he had a panoramic view of the long stretch that culminated on the beach, and lit the first cigarette. The gray sky of clouds augured rain.
    In absence of a pocket watch, it was the position of the sun, which, increasingly getting closer to the west, brought him the confirmation of what he already knew. He was on his fifth cigarette and his impatience was beginning to fade into disappointment. He was not so naive to suppose that something unforeseen had delayed him, and yet he would have bet his neck that Liam hadn't told him a lie the night before. It was clear that the cause of his absence was related to his imminent departure.

     Sherlock wandered countless times around, discouraged from looking for him but too embarrassed to return. He got frustrated with himself instead of getting mad at Liam. After meeting him and realizing how unique he was, he wanted to reveal the details of his life as if they were part of another mystery that fell into his hands. Liam became more than that, though, and the risk of pushing him away kept him from meddling where he wasn't called. In the end, Sherlock lost him anyway and the reason was inscrutable to him.

     The night had already fallen when he finally ran out of cigarettes. He closed the metal case and the urge to throw it into the ocean came over him, but the darkness of it made him reconsider. He looked up at the moonless sky. He was so engrossed in his thoughts that he forgot to pay attention to the passing hours. Where he stood on the dock was silent and dark.

     He leaned against the iron railing and sighed. He felt stupid; if that bastard Liam saw him he would mock him until morning.

     "Hey, what are you doing here at this hour?" Suddenly, an unfamiliar voice called out to him from the left. "Everything is already closed."

     Sherlock raised his face just enough to glance at its owner disinterestedly; the individual looked like one of those drunks who swarmed the beach taverns. Beside him, he noticed at least two more presences.

     "I don't have any money," Sherlock said, waving his hand for the other to leave. "Nor cigarettes."

     "Too bad, that's what everyone says" he heard a low, harsh laugh, followed by a hand rushing to his shoulder. He clicked his tongue lazily at what was coming.

     He didn't wait to be forced to turn fully, driving his fist into his flushed face. The man staggered, letting out a guttural growl, and his companions lunged at Sherlock amid insults of various kinds. They chose the worst possible victim for a robbery, but he realized that it was the same in terms of location. The dock was too narrow to get into a fight. Dodging their blows without hitting the railing was an almost impossible feat, even with his skills. He soon knocked the first down with a kick to the stomach and was about to do the same to the second, when the cold, stinging sensation welled up on his back. Then another pierced him just below, in the lower back, and suddenly his legs trembled. The snap of metal twisting in the flesh and then out of it overlapped the exclamations of those men, and he even stopped hearing his own wheezing.

     He fell to his knees, affected by the shock. He tried to slap them away as they stripped off his jacket and searched his pockets, but the stream of blood trickling down his ribs quickly weakened his strength. He coughed and more of it flowed in front of his blurred vision.

     They pushed his numb limbs away from him and forced him to get up. When they pushed his body against the dark bars, Sherlock knew well what they were planning. If he fell, the few chances he had would also sink. Panting and bathed in a cold sweat, he resisted, clinging to the frame. Then it occurred to someone to press their fist against his wounds. The sting poked his nerves like a flash of pain; a strangled cry rose from his throat and his hands finally slipped.

     "Toss him at once!" Demanded the individual who approached him first, after standing up. "I wasn't going to kill anyone, but we can't leave him here after what you did to him."

     "The bastard defended himself, and now it's my fault?" Replied another, upset. "These snobby ones don't usually react; I didn't know what to do."

     "And he had almost nothing on him. Anyway, we have to end this and go."

     The Atlantic looked no different than a hole in the ground several feet away when he was pushed to its confines. He broke through the surface and wasn't able to swim back to it; the impact stunned him and the air escaped from his lungs. At the mercy of the rocking waves, he would bleed out completely while drowning. He could not decide which option led to a more grievous death.

     Being the new moon, he did not see a miserable glow in the last instant of consciousness. The memory of Liam washed over him and he regretted letting him go.

Chapter Text

Slipping into death caused vivid hallucinations. Liam was there, in front of his face, holding a sharp dagger that he later directed against his own chest. He buried it in the pale flesh until it made a deep gash, and as the blood cascaded down his legs, he reached in with his hand to rip his heart out. Determination hardened his delicate features.

     Taking the muscle with both hands, he pushed it against his parted mouth. Sherlock bit into it, unable to resist the aura of urgency that surrounded him, and released a bloody chunk. It throbbed as if it was still alive, and the vibration didn't stop when he chewed it and passed it down his throat. The intensity of the sound increased, expanding in his mind, until it was deafening and led him back to the shadows.

     At one point he found himself with his eyes open. He wouldn't have noticed a difference between that and the inside of his eyelids if it weren't for a cloudy dawn rising in the sky. He breathed in slowly, believing himself dead, and a livid countenance loomed into his field of vision.

     "Sherlock, do you recognize me? Can you hear my voice?" He heard that person ask from the side, and it took him a few seconds to process that it was the missing Liam.

     "I do… I don't understand what the hell is going on, though" he replied, his mouth wrinkling at the salty aftertaste on his rough sandpaper tongue. He tried to get up but he stopped him.

     "Don't move yet" he said quickly, and only then did Sherlock notice his mortified expression, "there are a couple of things I need to tell you about first."

     "If you're going to apologize for keeping me waiting, save it."

     "It's related, but that's not important now," he replied, notably tense. "Do you remember what happened to you?"

     Of course he did. As his mind cleared, past events materialized to hit him in bursts of information. He had been thrown into the ocean as a corpse after being stabbed twice, and his rationality gave him no logical explanation for the fact that he was still breathing. Much less for the almost total absence of pain.

     He struggled to stand upright, ignoring the other's order. A heavy dizziness threatened to make him fall flat on his face, but he ended up sitting on the dry sand. He put his hand behind his bare back. Where the two deep, bleeding wounds should have been, he found a layer of thin skin that was hypersensitive to the touch. Stunned, he couldn't look up at the other man for answers; Liam grasped his jaw tightly and prevented him from looking at anything other than his own face.

     "They haven't fully healed yet" Liam pointed out. "I think that your internal organs will need at least a day to be in the same condition as before."

     Among so many absurd things, he still came to be surprised that Liam approached and touched him with such force. He lost his speech for a few moments.

     "Explain" he managed to say, narrowing his eyes at Liam's. "If not, I'll believe that I'm still dreaming or that I'm dead."

     "I pulled you out of the current and brought you here, though I wasn't sure you were still alive."

     "That answer doesn't tell me anything about this miraculous recovery. Those bandits made sure I didn't get up again."

     "I know" He lowered his gaze, tilting his blond head. Sherlock had never seen him so insecure; and although he kept silent for a moment to allow Liam to decide the best course for his ideas, realizing that he would not proceed, he took his cold hands and gently unhooked them from his jaw. Liam didn't try to avoid it, and his arms dropped.

     Unlike the hallucination that he had, when observing it he did not find any incision in Liam's torso; Sherlock's eyes descended down Liam's abdomen and braked abruptly as he reached his pelvis. He blinked quickly, skeptical of his own vision, but the image gave no indication of fading.

     On his hips, smooth skin gave way to what he identified as scales, which were red and gleamed in the weak morning light as if polished. They were intertwined with each other and covered a long tail that, ending in two fins of a darker hue, occupied the place where his limbs used to be. In those moments he was keeping it bent and tucked in on itself, as he would with his old legs, allowing him to rise into a sitting position next to Sherlock. He detected another detail just as surprising: two gills, oval and carmine, split like crescents above each clavicle.
     Sherlock might suppose that it was another dying delusion, if not because suddenly all the fragments that he collected in previous days were assembled to reveal the same truth that he had now inches away. Liam's presumed talent for swimming, the apathy he displayed in front of the ponds, and the motive that drove him to leave.

     Suddenly excited, Sherlock's mouth widened into a lopsided grin.

     "I knew you were hiding something incredible! It couldn't be something insignificant when it comes to you, although this beats all my hypotheses" he exclaimed hastily. "I considered the possibilities that you were an aristocrat, a criminal, or an intelligence agent, but I did not get to think that…" He fell silent when he noticed his right arm, the one that was bathed in dried blood below the elbow. He took his wrist to examine it before he concealed it behind his back, as it seemed to be his intention.

     "I think I get it" he whispered, his eyebrows twitching. A large chunk of flesh had been ripped from the inside of it, and even though it was no longer bleeding and looked to be healing, his muscles were still exposed. "We must do something about this, where was my shirt?"

     Liam withdrew his hand, not blinking.

     "There's no need. It will have regenerated before noon" he explained laconically.

     "It looks terrible" Sherlock said, unconvinced. He groped behind and found the bloody garment. He peeled off a piece and began to wrap it around his injured forearm.

     "Sherlock, believe me when I tell you that the last thing you should do right now is worry about it."

     "What nonsense are you talking? You saved my life, there's no way I don't care what happens to you."

     "No" Liam snapped at once. "All I did was condemn you."

     Liam then began the story, finally looking into his eyes, with a gravity that left no room for interruptions. He began by clarifying to Sherlock that the nature of his species was under the influence of the cycles of the moon, and that only during the days when it was in a new phase, that is, in the new moon, was he able to transform his body and mingle with humans. However, being absent for too long weakened beginners in the field, and therefore it was not very common to do it for more than a few hours each day.

     "I met you on the first day of the new moon," he said "and today is the last. After tonight I won't be able to get out of the sea until the following month."

     He later confirmed what was told in the legends: mermaids and mermen were immortal; After a certain age, they stopped aging and kept the same appearance forever. In relation to that, he hadn't lied to him about the number of years he had, although these didn't mean anything as he was an eternal creature.

     All of this led to what had happened the night before; After rescuing Sherlock and checking that his heart was beating, his only alternative to guarantee his survival had been to feed him his own healing flesh. Liam made him spit out the water, then held him up and forcibly stuffed into his mouth the small pieces that he severed from his own arm with the knife that he kept, along with some other items, at that isolated end of the shoreline. He used his voice to keep Sherlock semi-conscious during the procedure, which went on for hours; even when Liam managed to stabilize him, his injuries were still serious enough to cause his death later if Liam didn't make sure.

     At that point, Liam's voice trailed off. Hesitantly, he looked away at the makeshift bandage with which Sherlock covered his lacerations against Liam's will.

     "It is true that I prevented you from dying, but it's not just about having healed your wounds." He gave him a sour, sad face. Sherlock caught a glimpse of the unusual sharpness of his teeth, and in particular his incisors. "People who consume the flesh of one of my kind lose their mortality. It's something unnatural that should never happen. From now on you will not suffer from diseases, but you will not grow old either, Sherlock. It may sound like a good thing to you now, but I assure you that one day you will consider it a curse."

     Following the fateful sentence, he fell silent, although Sherlock still had unanswered questions. He watched Liam's fists, resting on what would be his lap, allowing the scope of such statements to sink into his brain. The life he led was the one he had chosen for himself and he was content with it; he never yearned for something as impossible as immortality nor did he fear death. He was used, in fact, to dealing with it in his work, to analyzing it from different angles, and he did not know how to feel when he received the impressive news that he was no longer going to experience it, that he would live without seeing an end.

     Sherlock took his hand and brushed his beautiful scales. He appreciated that they had the smoothness of a cut gem, as well as looking like one.
"There's no way I'm blaming you for what you've done," he said, with complete conviction. "You saved me using yourself when you could have let me rot at the bottom of the sea, and I actually love the idea of knowing your secret at last." He paused to grin at him sardonically. "You completely fooled me, you know? No one had ever done it before."

      He meant to cheer him up, but Liam's eyes darkened even more.

      "And that makes me no less than a demon."

Chapter Text

"In the space under the third rock, there's a suitcase I kept for emergencies," he had told Sherlock before leaving, hand pointing at the heap of huge boulders in one corner. "I imagine the clothes will be your size; take what you need and go back. We are half a kilometer from where I found you, but you only need to continue along the beach heading south."

     William felt his bare legs, which he had just recovered to move through the sand, weak as if it were the first time he was using them. Sherlock was watching him with perceptible fixation, but William did not turn to him.

     "Aren't you going to confess anything else to me? There are still things I want you to clarify for me. You can't just leave now."

     "I've told you everything you need to know. In case you doubt the veracity of my words, you are free to divulge what you have seen today. You are within your rights after what I did to you."

     "You wouldn't have saved me if you thought I was going to expose you," he heard Sherlock say after a brief silence, his voice dripping with disgust.

     "Who could know? I didn't have time to consider it," he replied cynically. William expected to make him angry, but defying his expectations, Sherlock leaned in and stopped him by grabbing his uninjured arm.

     At the warmth that his hand emanated again, William's eyes trembled; luckily Sherlock couldn't see it from his position.

     "Tell me, what guarantees me that you won't disappear again?"

     "You know where I'll always be, Sherlock; Until the day they lock me in an aquarium pond." His lips spread into an ominous smile, as he shook his fingers off him.

 
     When he was in the ocean, William's senses were those of a predator. Once blood was spilled, he was able to perceive its effluvium and trace its origin from miles around. The characteristics of it let him know if it sprouted from an animal or from a human being; the latter used to be unmistakable due to the density of its aroma, and it was precisely thanks to this that he found his inert body so quickly, despite the fact that the current kept dragging him.

     Although he had not attended their meeting at the dock, he spent the afternoon swimming around it, feeling uneasy. The temptation to spend the day together one last time made his heart pound; but unable to give him honesty, he became convinced that it would do Sherlock no good if they were to interact any longer. An immediate disappointment was preferable to Sherlock discovering they weren't even of the same species. He put the consequences first for both of them, although, being such a unique and sagacious person, he failed to predict how he would react with absolute certainty.

     However, misfortune fell on him, and he could not intervene to prevent it. He prided himself on being able to control his emotions under any circumstance; but the horror he experienced when he found Sherlock unconscious, bleeding like shark bait, William would not forget even after being alive for a century.

     No matter how fast he could cover long distances, William knew it was too late to save him; he took Sherlock to a secure location, but he had no way of stopping the bleeding using conventional methods. Sherlock's life was slipping away from under his powerless hands. Seeing them soaked in his blood, William conceived an atrocious idea and set off, not having time to hesitate. The edge of the dagger, which was almost indistinguishable in the dark when he drew it from the hidden pouch, penetrated his skin cleanly. He slit it into his arm over and over again, ignoring the pain, and then put the sticky pieces inside Sherlock's mouth. "Chew and swallow," he repeated this command in Sherlock's ear in the special voice few beings could resist, knowing that it would reach him through slumber.

     After a torturous couple of hours in which William thought it might be useless, the wounds on Sherlock's back closed. Watching him sleep, William became aware of the sin he had committed, and the fact that Sherlock did not blame him upon learning the truth did not help diminish the renewed sense of guilt. This was taboo, and it was often interpreted as punishment for anyone who hunted and devoured the flesh of a mermaid. Now Sherlock was to carry it, despite being innocent, due to William's selfishness.

     As he nearly lost Sherlock, William's mind and heart clouded with anguish and he clung to him desperately. He would have done anything to keep Sherlock alive, and the knowledge disturbed him.
     Throughout his life he had felt interested in the world of earthlings and learned to pretend to be one of them from a very young age; he imbibed their culture, which he learned from the pages of books, and wanted to repay them by lending them his vast knowledge. He witnessed the goodness of many people, and also the misery and evil of many others. The powerful used their privileges to oppress those they had under their yoke and society was corrupted without remission, even in a town like that. He feared that the ocean would also end up being polluted in the end.

     Then someone like Sherlock Holmes appeared, with his carefree attitude and confidence in uncovering truths, and reminded him why he had ventured out of the seas in the first place. He was another outsider, and in just a few days he made him forget that he wasn't supposed to be there, among human beings. He befriended him without asking for anything, and caused, without suspecting it, his home to seem lonely and silent. Furthermore, he instilled in William the hope that the country would not completely collapse as long as there were such individuals. That thought partly alleviated the bitterness of parting, and in turn, it became another reason why letting him die seemed unacceptable.

     "... We can get out of here, I don't care," proposed his brother Louis, overcoming his perplexity and trying to take a load off William, when he revealed what happened without keeping the details. "That way you won't have to worry about him anymore; You already did a lot for that man, brother. The least he should do is thank you by keeping our secret."

     His words seemed to condense in the coldness of the silence that reigned within the cave. This was one of several underground spots where they congregated after their excursions into the mainland; its existence went unnoticed even by a good part of the fishermen and therefore they did not have to worry about being discovered.

     "I owe you an apology as well," he smiled and looked away at the crystalline pool in front of them, on whose surface their almost identical reflections materialized. "The risk of showing myself to someone in this way doesn't just involve me. I had no right to make such a decision without consulting you."

     Unlike him, Louis preferred to avoid dealing with strangers and only left the waters to keep him company. No wonder he was cautious: it was just the two of them in that corner of the ocean and he had heard from William the rumor circulating in the region of the supposed mermaid sightings.

     "I don't know that Holmes and I honestly never expected something like this," Louis said and leaned down, looking at him through his reflected image. William looked paler than the absent moon and his lips were trembling, "but I know you always act in the best way. If he's as smart as you told me, he should be able to appreciate it too."

     William avoided clarifying that it was him who was not able to see it like that. That night he sank to the ocean floor, unable to give himself up to sleep, wanting to undo what was already done. William regarded his arm with contempt. If he could offer his own life in exchange for withdrawing the detective's immortality he would do so fearlessly, but there was no such miraculous exchange. Human legends told half-truths; the truth is that no mermaid could change his condition. Even if he shed tears of regret for the rest of his endless existence, no one would take pity on his misfortune. After all, they were no different than seawater.

Chapter Text

As it was the only place Liam used to stop by, as he had confirmed himself, Sherlock returned to that sector of the beach during the following days. Knowing that it would be impossible for Liam to leave the sea on both of his legs did push Sherlock to not give up; he believed that sooner or later he would come to the surface, as was his custom, in some corner sheltered from intrusive glances. He also found out about locations where sightings of strange creatures had been recorded and visited one after another. Although he was unsuccessful he knew that Liam was there, diving somewhere in that immense body of water, and he just had to wait or force him to resurface.
 
 He gave little thought to the fact that Liam was not human. It would not be a lie to say that when Sherlock saw him he had been so dazzled by his appearance that he could have convinced himself it was a dream, or that his mind exaggerated Liam's characteristics, but in no case did it cause him concern nor make him want to reject him. Liam was still the most fascinating person he had the fortune to meet, and when Sherlock looked at himself in the bedroom mirror and found no scar on his back, he ended up remembering the placid expression that Liam's eyes acquired when he smiled at him; the sadness he showed on the dock when he told him that he was sorry to leave. Compared to the experiences they shared, his nature was inconsequential.
 
 He decided to give himself a few days to reflect before continuing with the search; he had to find out certain things about himself and it was time for him to return to London to regularize his affairs. Otherwise, he was afraid that his landlady would end up throwing his things out on the street.

 Sometimes when he was asleep he saw himself wandering the gloomy corridors of the Brighton Aquarium. Liam put his hand on his shoulder and leaned over to comment on the butterflyfish or the habits of turtles; His soft voice was clearer to Sherlock than the memories of him. However, the next time Sherlock blinked he was no longer next to him. The surroundings were silent, the ponds empty. He was making his way back, ravaged by confusion, finally meeting him as he turned around a thick column.
 
 Liam was held captive in a tank that encompassed the entire view, floating near the glass with his eyes closed. Even though Sherlock's heart burned with the desire to free him, he always stopped, stunned, looking like one of the pillars, when he was about to strike the transparent wall with his fist. Liam had raised his eyelids and Sherlock's dream faded around his impassive gaze.
 
 Once his anguish was over, if he drew one conclusion from such nightmares, it was that instead of waiting for Liam to go to the mainland, it would be easier for Sherlock to enter his world.
 
 He noticed the calm waters from the height of the West Pier, leaning over the railing. Unlike the night when he was mortally wounded, the half-filled moon shone its light over the shoreline. The memory was so vivid that for an instant he seemed to feel a stab of pain piercing his back. Without thinking more about it, he untied the laces of his shoes, and after removing them and leaving them on the edge of the platform, he put one foot on the first metal bar. With adrenaline pumping through his veins, he took a long, deep breath. Then in one leap, he plunged into the icy ocean.
 
 After his fall he offered no resistance against the unforgiving waves; It wasn't just that he was looking for Liam, he was also eager to test his own limits. During his stay in the capital, he conducted some experiments on himself to gauge the extent of his resistance. Liam specified that the passage of time would not leave traces, just as he would not be vulnerable to disease; but he still had to uncover how his system would react to other threats. He cut his hand and arm with a scalpel, revealing that small and medium-sized wounds completely disappeared within thirty minutes. The marks made by a syringe did so in as little as two, and in the case of burns produced by fire or acid, the healing time did not exceed three hours. With those pieces of evidence, he could suppose that few things would mean a real danger to him.
 
 He wondered how such an extraordinary regenerative ability would work if his lungs filled with fluid. Would it keep him conscious until he expelled everything? Would he absorb it like a sponge? He also had to consider the probable factor of hypothermia. He was prepared to continue pondering hypotheses, at the same time that his oxygen was running out, when an imperious force tugged at the collar of his jacket from behind and dragged him in a straight line and then upwards, at full speed.
He surfaced as if the entrails of the sea spat him out. He coughed against the starry sky. As he shook himself, he brushed against a solid surface and realized that he was near the rocks.

 
"I shouldn't have rescued you the first time if your wish was to die," said the voice he had been waiting to hear again.

 
He turned to his right and found Liam watching him sternly. His wet hair clung to his cheeks.

 
"Even if it was, now I know it wouldn't be so easy for me," Sherlock said, smiling with satisfaction at having summoned him so quickly. “I’m lucky that the only merman I know doesn’t fit the stories that are told and comes to my aid.”

 
"Since you've paid attention to those myths, you shouldn't forget that humans were part of the diet of my ancestors," Liam replied curtly.

 
“You're not going to scare me off with that, Liam, and even less will you make me repudiate you.” Sherlock started to approach him, bridging the short distance as his jaw clenched and he shivered with cold. “These bloody frozen waters… if I was like you I'd look for a nicer place to frolic on a rock.”

 
Liam retreated into the darkness.

 
"I was lying to you and I put a curse on you," he argued, holding his ground firmly. “Both are good reasons to do so.”

 
"I'm telling you that none of that matters to me, how many times do I have to repeat it?"

 
“You don't care because you don't want to understand what it means, despite your intellect.” The pair of scarlet eyes flashed furiously, like a blaze in the middle of the sea. “When the centuries pass and you cannot fill the emptiness of your existence, you will remember what I told you and you will wish you had never met me. And then maybe you will come to get revenge.”

 
"Why did you save me then, if this is supposed to be worse than being dead?" He inquired, brushing the wet locks from his forehead. Exasperation was beginning to flood his judgment. Except for the absurd idea of retaliation, none of those things escaped his imagination. It wasn't much, but he had enough time to clarify his feelings for Liam, so he wouldn't accept such arguments. “What was it that made you actually do it? I want you to tell me.”

 
Given how evasive Liam could be, Sherlock boldly reached up and grabbed him by the chin. He wasn't the first to invade the other's personal space, he told himself, noticing the degree of surprise and dismay that showed on Liam's face.

 
"You didn't deserve to die like that," Liam argued, avoiding his gaze, "and if you hadn't waited for me, nothing would have happened to you."

 
“Those things happen; I could have had an accident on the railroad or at work. It couldn't be just because of that. Also, clarify to me what it was that led you to spend time with me despite the risk of exposing yourself.”

 
Liam cocked his head to the side to shake off his touch. He closed his eyes briefly and the tension in his face gave way to resignation.

 
“Now you know what kind of creature I am; you are seeing the differences between us. What I have felt is no excuse for ...”

 
"Who you are and what you felt is enough for me," he interrupted, raising his voice. “I've been seeing you in my mind all this time since we parted ways, and I can't stop doing it. And I'm not saying it because you're half a fish, I don't give a shit about that.” Sherlock fell silent and his lips pursed. Expressing it verbally was perhaps the hardest part of the whole thing, but if he didn't go through that embarrassment he risked losing him. “In fact, I decided that a lot of things didn't matter to me the moment I realized what you are to me, Liam. Saying that I see you as a friend ... no longer seems accurate.” He reached out with his right hand and brushed his bare shoulder, the gesture completing his message as if it weren't obvious. Liam had to look back at him at last, and he did so with an expression of surprise bordering on disbelief.

 
"It's a lousy idea," he sighed as he gathered himself. He gently took his cold hand and held it close to his chest. “Loving me will only bring you suffering.”

 
"I'll be more miserable if you keep hiding from me, and I know you will be too. That we have time to spare is no reason to waste it.”

 
"I can't live in your world and you can't live in mine, what are you expecting? You will be disappointed in the end.” Liam tilted his face toward his questioningly. Frustration clouded his features. Sherlock was unfazed by his hopelessness, he put his free arm behind Liam's waist and pulled him against his own body. He felt Liam's tail wag under the water.

 
"You have lived a double life for five, or maybe ten years? I'll just have to join it.”

 
Face to face, they hugged each other in silence, barely moving by the gentle swaying of the waves. He might be shaking, but he wouldn't have let go of him even if it meant sinking. Liam didn't do it when he was about to perish; and if he didn't give up then, Sherlock wouldn't give up now either.
 
 "And what will happen next?" Liam asked later, with his eyes downcast, "Do you plan to extend this drill for the rest of eternity?"
 
 "I have better ideas," Sherlock said, with a smug smile. “I assure you that I’ll find a way to be near you at any moment, and you will no longer feel alone in this wasteland. Take it as a promise.”
 
 Hearing it, Liam tilted his face to giggle.
 
 “I don't think anyone has ever promised something so impossible to a member of my species. In case you are wondering, you will not get gills from having eaten my meat.”
 
 "I'm not going to need them either, and even less to kiss you." Laughing too, he cupped Liam's face and attacked his elusive lips. Considering that his empirical experience in matters of love was practically nil and that he acted on impulse, that salt-flavored kiss was clumsy and careless. Liam moved in time with him, and the warm puff of his breath loosened Sherlock's mouth.
 
 "I'll wait to see it, no matter how long it takes," Liam said as he regained his distance, his smile brighter than the shy stars hidden behind the clouds. “That will be my promise to you, Sherly.”

Chapter Text

Liam had told him that living forever would be a curse; a century later he still did not consider it such.
 
 With the addition that Sherlock began to visit him at least once a week, at that time he continued living in the same way that he had done until before meeting Liam; he kept his job as a consulting detective, handling cases that were of interest to him, and eventually landed a roommate. Dr. John H. Watson, of honest nature and affable attitude. He became his collaborator and friend, which made his days in London less lonely. In that way, time began to pass, and he would not even have noticed if it weren't for the fact that his lover made sure to comment on it every time.
 
 “You have to be careful. They will soon begin to notice that you’re not getting old. What do you plan to do?”
 
 As he delivered this warning, Liam held Sherlock's face in his long, soft hands. They were resting in a desolate corner of the coast, and by then it would have been close to a decade since they have decided to stay together. However, the only physical change in himself was that he had stopped tying his hair in a ponytail to wear it loose and long around his shoulders.
 
 "The day I can't hide it anymore, I'll move closer to here," he said, and he remembered tilting his head to press his lips against Liam's skin. “I still have to work on my plan, but it will be better than being an hour away.”
 
 "Isn't that enough? Even if we don’t live in the same place, it will be in the same city. We will be able to meet daily.”
 
 "I already promised you, did you really think I'd give up eventually?"
 
 "I thought that reality would creep into your mind little by little every time you saw me." He gestured toward his body, toward the tail on the sand whose red scales gleamed in the sun's rays.
 
 “A myriad of things come to my mind when I see you, believe me, but giving up is not one of them.” With that, he got a sarcastic smile.
 
 "It won't be easy from now on," Liam warned later when he hugged him with affection. “It's only been a few years.”
 
 Sherlock might have found his fixation on the subject funny if it weren't for the fact that he hated the way Liam kept blaming himself for what had happened to him. After starting to date him Sherlock had to overcome quite a few of his barriers; He had to show him that his feelings were sincere and not the result of a simple whim, that Sherlock was indifferent to Liam's appearance, and that he was never going to betray him by revealing his secret to the world, even though Liam already knew that. . Nothing helped to completely eradicate that stain of regret, despite Sherlock deciding to take his new status to his advantage. Only then would he have the opportunity to dedicate himself indefinitely to the things he was always passionate about and to share his life with Liam.
 
 Ultimately, he was left with no choice but to withdraw from his family and friends, or rather allow them to leave him behind. Their paths had parted, and although he could use a few tricks to keep them from suspecting that one day he would become an eternally young fossil, he saw no purpose in prolonging the charade each day. He was sure that at least his brother would have found out; but Mycroft left him to his own devices and never asked, not even on his deathbed, decades later.
 
 More time passed and the evolution of society brought with it two world wars and incredible progress whose characteristics he could not have imagined. Cars, electric power, and even something as chimerical as the birth of the internet. Given his fondness for science, the 20th century kept him on edge for every decade, and Liam must have listened to him theorize for hours. It was one of the things that kept him from succumbing to the onslaught of boredom, and the loneliness that hit him from time to time when Liam wasn't around.
 
 Although with a little more caution, Liam too was following the events that were taking place around him with interest, especially regarding his habitat:
 
 “It doesn't bother me that people have lost their fear of the sea and dedicate themselves to diving on weekends, but it’s increasingly risky to come to the surface without being captured by a lens, '' Liam told him one day after the advent of the new moon. “I think it's time to go somewhere less crowded, Sherlock.”

Seeing his carefully impassive expression, Sherlock concluded that perhaps a part of Liam doubted that his resolve would remain intact after a century. In a way, Sherlock had been waiting for Liam to tell him: after studying the coastal terrain above the surface, and below it thanks to Liam's knowledge, as well as the land of other nearby cities, he finally found the right place to put into practice one of the ideas he had worked on for years. The technological advances were not in vain, not even for a couple of extemporaneous like them.
 

 The new property stood a safe distance from the cliffs. Despite being clad in stone and wood, which made it more solid, from the outside it was no different from a nondescript cabin. He would often find Liam sitting by the long windows looking at the ocean, or just asleep under the warm afternoon light.
 
 When Sherlock saw him fall unconscious in any place, he was sometimes worried that if it happened under the water Liam would be dragged away by a fishing net; but then he remembered that Louis, his younger brother, would surely be with him and would take care to avoid any such nonsense. Although that guy didn’t hold him in very high esteem and seemed to detest him when his lover introduced him, more than ninety years ago, Sherlock could trust that he would not fail in that task, not even at the risk of his own life.
 
 Sherlock left the radio on while he prepared dinner and music at low volume filled the space that encompassed the living room and kitchen. Preparing food was one of the things he had not been particularly good at in the past, but after having experimented for such a long time he could take pride in his progress. Even Liam, who used to feed himself on nothing but fish when he roamed the sea and possessed a rather dubious sense of taste, must have admitted it in the end.
 
 After putting the lasagna in the oven he glanced at the cell phone on the side of the counter; it was almost time for him to set out to meet Liam. He wiped his hands on a cloth and went to the bedroom to pick up the white robe that hung from the hook on the door. Tucking it under his arm, he led his steps toward the basement. The trapdoor that led to its cavernous entrails was hidden under a geometric-patterned rug at the end of the hall, and as soon as it was lifted, the cold, salty breeze caressed his face as it did every time he went downstairs.
 
 He fiddled with the light switch by the wall and the narrow path of stone steps lit up. With irregular contours, the passageway that had taken them more than five years to build led to an underground cave that was smaller than the living room, and except for the clarity provided by the last spotlights on the lintel, the place remained in a peaceful semi-darkness. Right in the middle, a pond connected this natural refuge to the ocean, its faint roar bouncing off the warped walls.
 
 Upon arrival, he found Liam's slim figure sitting on the edge. His back was turned to him and Sherlock glimpsed his legs re-materializing.
 
 "I insist that I must illuminate this place more," Sherlock said as he approached him. “Spending the night here is kind of depressing, no matter how you look at it.”
 
 "You've done enough," Liam said and turned to give him a reserved smile. “It’s not good to intervene in the environment beyond this. And I remind you that you are the one who prefers to stay here longer than necessary when I can't go up with you.”
 
 "I have to keep my promise, right? I said that I would see you whenever I wanted.”
 
 "I'm sure those were not your exact words."
 
 “The substance matters more than the details.” Sherlock reached out to help him up on the slippery surface.
 
 Liam straightened slowly, his gaze penetrating without taking his eyes off Sherlock's. They were silent for a few seconds, gazing at each other with an affectionate fixation until Sherlock reacted and spread the bathrobe over his shoulders.
 
 "You better not have filled yourself with fish already, because dinner is waiting in the oven," he snapped, at which the other shook his head. A hint of irony crept into the curve of his mouth.
 
 “I wouldn't miss your culinary experiments, Sherly. What is it this time? Asian food? I've heard that vegetarian dishes are all the rage.”
 
 "Finish putting that on and come see for yourself before it burns," he said and waited for Liam to finish tucking his arms into the sleeves and tightening the belt. The moment he lifted his face, Sherlock's lips kissed him. “Welcome home again, Liam.”
 
 "Glad to be back," he whispered, pressing his mouth to his one last time.
Liam reached for his hand, and Sherlock dismissed the previous comment in his mind: his scarlet eyes, gleaming in the gloom, were all the light that was needed in this place.

Chapter Text

 Even below the surface, the red scales on Liam's tail glistened as he drifted to the edge of the boulder. If it were the first time that he saw him navigate in the sea, he might have believed that having such an eye-catching physique would be a disadvantage for him; but Sherlock already knew well how Liam's speed helped him to avoid danger and predate upon his marine prey. It was understandable that no one had ever come across a mermaid specimen and he prided himself on being an exception.

 
From his place, a few meters away, Sherlock watched him pull the black bag that had been left there. Then Liam turned and swam back to him, looking graceful despite carrying a heavy bag of garbage. Sherlock helped him hold it and together they prepared to emerge.

 
"Let's leave it for today," Sherlock asked him, after taking off the snorkel's mouthpiece. “How many hours have we spent at this, anyway?”

 
Liam, who had just momentarily left that bundle among the rocks behind them, looked at him suspiciously.

 
"It's only been two; But if you are very tired and find it a nuisance, you can go ahead.”

 
"I didn't say it was," Sherlock growled, brushing off the long wet hair that fell over his diving goggles. “But I’d rather go elsewhere when you can get out of the water.”

 
“It's what we always do, Sherly. This type of work, on the other hand, does good for the community. Yours and mine,” Liam said with a conviction resistant to his complaints and dived again before Sherlock blurted out another objection.

 
Clicking his tongue, he readjusted the tube and lunged after him. Cleaning up someone else's mess was perhaps his least favorite task on earth, but Liam's concern and contempt for the pollution of the seas had a long history and Sherlock was not so inconsiderate as to sit on the sidelines as Liam spent his days dragging away waste. In exchange for him not overdoing it, Sherlock had agreed that he would dedicate some of his spare time between weeks to help him when the weather was right. And there they were, circling in shallow water as the sun's rays faded progressively.

 
"You're going to make up to me for this," he demanded after finishing, tapping Liam's white forehead with the tip of his index finger. He was on his back, on top of a towel laid out on the damp sand in that nook by the rocks, and Liam was leaning over his face with a calm smile. “The world can wait for you to save it.”

 
"I thought watching me swim entertained you enough to make up for it, or have so many years killed your curiosity about my species?"

 
"You and your species are separate things," Sherlock replied, sitting up. He yawned wearily and dropped his head onto Liam's shoulder, "and you won't get away with that alone this time."

 
"It should be the other way around, but you've become more capricious over time," Liam observed, with more leniency than reproach. He wrapped his arms around him and began to untangle his tousled black hair.

 
“And you are no less ruthless than before.”

 
Sherlock sighed; the sinuous movement of those fingers over his scalp made him feel even more lethargic and his mind unraveled in a tangle of ramblings. In the 21st century, there were endless opportunities at his disposal that he didn't want to waste: they could go around hand in hand, kiss in the middle of a crowd, and they wouldn't break any laws in the process. They were even allowed to marry the same as heterosexual couples, an instance that Sherlock would not have thought he could see with his own eyes. He wondered if the same recognition would occur in the distant future with creatures like Liam if they ever came to light.

 
He tightened his arms around Liam's waist, soaking up the moisture from his warm body. Then, remembering a conversation they had earlier, he chose the most insane of occurrences to interrupt the silence:

 
"If mermaids usually mate during the new moon, do you think they still do so near the coasts?"

 
"I knew that one day I was going to regret having confirmed it to you," was Liam's reply, after a few seconds of confusion. He lightly tugged on a few dark locks. “Before you go any further, let me clarify that I do not share the exhibitionist fantasy.”

 
"Do you have any other?" Sherlock raised his face with a scowl full of malice; the comment earned him another tug. “Bah, that would attract less attention than the form you have now.” He released a hand and stroked where Liam's thigh would be. If it was the soft touch of his scales, he was never satisfied.
 
 At the dawn of their history together, Liam used to be reticent and embarrassed when Sherlock gave them his attention and sprinkled kisses on them; it was as if it was inconceivable to him that Sherlock felt comfortable touching him. Now, however, he didn't even pretend to stop him because they were away from the privacy of their home. Liam rested his right hand on top of Sherlock's and his shoulders moved up and down as if he were releasing a sigh.
 
 The warmth began to increase and soon gave way to the unmistakable smoothness of lush skin. Instead of glancing down to discover the obvious, Sherlock turned his gaze to those silent lips. Their pallor awakened his appetite and he reached over to satisfy himself.
 
 Before he reached them, his lover's quick hand sealed Sherlock's with his fingertips.
 
 "The rubbing of wet sand is uncomfortable if you have skin," he said, narrowing his eyes at Sherlock's scowling expression. “I would appreciate it if you would do something about it.”
 
 "Just stop wasting your time and come here before it gets dark," Sherlock laughed and grabbed Liam's hips to lift him onto his lap.
 
 As soon as he had him there he began to kiss him; he entertained himself by sipping the sunlight that spilled like honey over the curve of his neck and made his blond hair glisten. Liam's breath hitched, thickening against Sherlock's cheek, and his fingernails outlined his bare back. Sherlock was painfully aware that only the thin black fabric of his bathing suit kept him from melting into his warmth.
 
 "Isn't it a shame I can't stay in this shape, your favorite, indefinitely?" Liam pointed out wryly, wrapping his arms around Sherlock's shoulders. “It would be your ideal reward.”
 
 Sherlock stopped licking his jaw and regarded him with a raised eyebrow.
 
 "Who says I have a favorite?" He replied seriously, "I know what you're thinking, but you've put too many fantasy books in this head of yours if you think I'd change something about you for convenience." 

He tapped his temple for emphasis. Liam made that dubious expression Sherlock liked to tease by kissing it off.
 
 "Then we would be a normal couple, I don't see why you wouldn't like the idea."
 
 “Tch. We’re already that and in a much more interesting way, ” he assured, holding Liam's face with both hands so that he could see how serious his words were. “So much talk is killing the moment, is that what you're really looking for?”
 
 "If so, maybe you weren't very willing from the beginning," Liam blurted out with a mocking tone, leaving the subject behind.
 
 "You're wishing for me to prove it to you, aren't you? You like to have fun at my expense.”
 
 The teasing smile Liam gave him stayed on his lips as he kissed them hard. He breathed in the salt that covered that chest of his, forgetting the coldness of the breeze. And when a delicate hand buried itself in his crotch, the sound of the ocean and the humidity also disappeared.
 

 When he washed his hair in the shower, he discovered that even behind his ears there were grains of sand attached.
 
 "I warned you it was better to stop." Liam didn't miss the opportunity to rub it in his face when he heard him groan through clenched teeth. “Do you want me to show you some places away from the coast, next time? Although I'm afraid you will need an oxygen tank.” As he spoke, he stopped rubbing soap on his arms and turned to shove his hands through Sherlock's black hair.
 
 "To help you pick up trash? That trap is predictable.” He snorted, but found relief in Liam's fingers on his scalp.
 
 Liam gently massaged through the foam of the shampoo; Sherlock looked at his face in the steam that filled the bathroom, his warm eyes fixed on the task, and returned to the thoughts that had arisen that same afternoon. He could not imagine a happier life or anything else he could wish for; he delivered on his promise and they could be next to each other despite the differences between their species. Neither time nor absence of the other could make a dent in his feelings. On the contrary, they reinforced them. Even so, the remnant melancholy that he sometimes noticed in Liam's eyes did not escape him.
 
 Immediately, he blurted out the proposal, which seemed like a logical way to show him how he felt:

 
“Since it’s now possible, perhaps we should get married. Ceremonies seem unnecessary to me, but you can frame the certificate next to those math articles that you love so much.” His lover continued what he was doing for two more seconds. Then, processing what he had just heard, he stopped, slowly lowered his arms, and directed his sharp pupils to Sherlock's resolute expression.
 
 "I doubt I heard wrong, but clear it up for me: did you ask me to marry you right here and now?"
 
 "Romantic things don't go with me," Sherlock defended himself, turning his face away. Such scrutiny made him feel ashamed. “Didn't you want us to look like the rest of mortals? Getting married is what they usually do.”
 
 “But wedding rates have fallen in recent years.”
 
 "If you don't want to just say it, leave numbers out of it," Sherlock growled, twisting his mouth. “I'm not going to drag you down the aisle.”
 
 Liam smiled in the sweet way that made his heart melt like butter and immediately turned on the water. The gentle rain sprayed again on their bodies.
 
 "I would never want to say no," he admitted, bending over to press his forehead against Sherlock's collarbone. “You have gone so far for me, for us ... and it will be an event to see you dress in formalwear.”
 
 Sherlock threw back his head and laughed. He put his arm around Liam's back and they were close to slipping. Despite his warning to be careful, in the end, Liam ended up joining his laughter as he clutched the translucent curtain.
 
 "It will be less annoying than carrying a tank while I hug you," he declared.