Archive of Our Own

Even when the trio had been younger, Senku was always buried deep into his research.

Taiju and Yuzuriha would remember the days when Senku would be deep into his research late into the night, they'd ask to sleep over, his response always being the same.

“I don't give a damn, do what you guys want. Just don't mess up the house.” He'd say, muttering softly as he turned to them slightly so they knew he at least acknowledged their existence.

They both would sleep over, checking up on Senku, only to find him asleep in a pile of papers and parts all over the place.

They'd clean up, Taiju would carry Senku only to his bed, tucking him in and saying — “Sleep well, buddy!” The quietest he could.

It was never quiet, but Senku was a pretty heavy sleeper. But it always got Yuzuriha's anxiety high, Taiju would only apologize a little softer after and help with the cleaning once making sure Senku was tucked in and comfortable where he laid.

Those days were always nostalgic to look back on, the days before the stone age came back.

The days before they were petrified and whatnot.

So seeing it first hand again was almost shocking to both of them. Taiju couldn't help but feel a little giddy inside seeing Senku so deep into his work. Yuzuriha could say the same, but she was always worried if Senku was taking care of himself or not.

It became the same loop as before, them cleaning up Senku's mess as soon as he knocked out in his work.

Until one day, that is.

Gen knew about this cycle; he always watched it with a fond smile. He knew the trio were close, and it was almost idiculous-ray how rhythmic it had been.

I mean, it was a constant loop. He'd always watch the sleeping Senku be held carefully by the ‘big oaf’ himself and onto his bed only for the man to practically shout in his ear. Then Yuzuriha would give him a soft look, Taiju would apologize then help clean.

UTTERLY idiculous-ray, in Gen's opinion.

Not that it mattered. Even if he talked to Taiju about it, poking and prodding at the idea of him possibly being used, Taiju would only give him a loud, optimistic response.

“NO! Senku would never do something like that, he's just a busy guy! It's the most we can do to help him out!” he’d say with a bit of an offended look before turning around skip off.

It was almost the same when he talked to Yuzuriha about it, instead it was a more calmer, softer response.

“No, no, it's not like that at all! Taiju and I do this because we want to. Senku works so hard to bring back humanity even if it isn't his job. He deserves to wake up without soreness in his neck atleast.” she’d say with this smile on her face as she looked at Senku with this look of admiration before walking off to go sew some more clothes for other people who were beginning to be revived.

So when Gen walked over to Senku's area, he hummed softly with a pleasant smile, knowing full well he was simply strolling over here to bother the scientist only for him to walk into Senku's relaxed, sleepy state. He paused.

There he was, the mad scientist himself, slumped over the messy science work and literature handwritten by him.

Gen's eye twitched, his mouth being left agape for a moment.

“Are we erious-say? He fell asleep again?” The split-haired man muttered softly, sighing as he dropped his arms to the sighed.

“Is this how Taiju and Yuzuriha feel?” He couldn't help but wonder as he stepped next to the sleeping man and poked at him.

He let out a pout, looking to the side and narrowing his eyes in thought.

“Well, he doesn't look..that difficult to carry.” He said softly, looking at Senku with a nervous smirk. “One could only hope.” He added with a begrudging tone before slowly reaching over to Senku and gently pulling him off the desk.

He took a deep breath, picking the man up. Gen was certainly correct; he wasn't as heavy as the others.

It wasn't a total shocker, though; the man never really took care of himself all that well. Always buried in his work like mentioned before.

He smiled fondly, shaking his head and looking at the man's sleeping form.

His breath hitched then, his eyes growing wide slowly.

He looked so..

peaceful

Sure, it was no surprise since he was sleeping, but it was different. Senku always had one of 3, maybe more, faces:

A shit eating smirk
A serious look
A thoughtful look

And sure, there were SOME inbetweens but other than that.. He was always so thoughtful. In the scientific way, at least.

He wasn't very considerate of emotions.

Oh well, he has his way of showing his care.

Afterall, in the past Gen could only dream of his fresh, nice and cold cola before, it became a reality because of Senku.

Going back to how he looked.. It was nice.

Gen didn't forget the man was handsome, how could he? Many women swoon over the guy, no matter how harsh he can be. If he wanted, he could probably have a harem.

Good thing Senku wasn't a scum bag, not a big one, at least.

Gen's vision narrowed as he admired the sleeping man's face. His lips parted slightly in a slight shock, only to form a gentle smile as he cupped his face gently. His face was admirable, it always had been, especially because it was the same guy who would always be smirking at Gen and ordering him around making him drop dead in bed everyday.

He quickly shot his hand back away from the other's face, realizing just how creepy that could be.

A nervous look splattered on his face as he shoved his arm under the scientist and carried him to a bed nearby.

He tucked the man in and called it a day.

No, he didn't stand there for a while with the world's softest smile on his face. And no, he did not enjoy seeing the man so relaxed.

Maybe he did.

But you couldn't blame the mentalist, after all, Senku worked himself harder than he worked anyone else. His brain is always on, always thinking. He never gave himself time to relax, always shoving the break away and saying— “We've got no time to slack, get back to work.” or something along the lines of that.

In the most genuine way, Gen is surprised the man hasn't gotten sick yet or anything. The amount of stress on the scientist's shoulders is huge yet he just picks at his ear, smiles and shakes his head like it's nothing.

As a mentalist, it's natural for Gen to be so..interested. Usually people would be crippling under some sort of stress but Senku is handling it like a pro. He has to admit, the guy is seriously impressive.

—----------

So, it's known that Senku doesn't have the best luck sometimes. Especially when an idea is thrown into existence whenever Senku or someone else says something that is absolutely erible-tay and then it becomes a reality.

Well, it turns out Gen simply muttering about how shocked he was that the scientist doesn't get sick also applies to this rule of manifestation because now Senku was lying in his room burning hot.

Gen's eye twitched as he heard Ryusui cackle in the background, talking about how Senku finally succumbed to the pressure of whatever the hell kind of project they were doing. Sure, this was all fun in games but as soon as the blonde captain stepped into the room his smile dropped for just a second once he saw the feverish scientist.

He definitely was sick to say the least.

His eyes being red and teary eyed meanwhile his nose was also red and stuffy. The scientist's chest raised shakily and heavily, a sign of shortness of breath which didn't help considering the man's asthma diagnosis that Taiju mentioned to defend Senku when Gen teased him for not being able to run for long. His body shivering despite his face being red as a tomato and as hot as freshly made soup.

Both the mentalist and the captain paused at the sight, the two of them having a slightly anxious look that was a deeper meaning of pure concern. All of them had grown close, especially since they came from the same era.

Not only that, but the most important factor was that Senku is one of the most important people in the group. If he goes down, who knows what kind of chaos would happen?

Senku tried getting up and doing work, but that only ended up with Taiju dragging him back in bed and Yuzuriha fussing over the man.

Gen couldn't help but watch the scene with a fond look on his face, yet a look of concern was soon thrown into his face as soon as he heard the raspy coughing and wheezing from the man in the bed.

Now, Gen is a pretty shallow guy (or, he believes he is, despite being the opposite.) but that doesn't mean he doesn't have morals. Not only that but he was the only person in the room currently and everyone else in the boat had been doing other things for the sailing mission.

Gen stood there awkwardly for a moment, staring down at Senku with a nervous look.

“The hell you looking at, mentali-” He coughed, covering his mouth with his elbow while the other hand clutched at his stomach which only led to Gen flinching and making a small face, his sleeve raised up to his mouth as he looked down at the man.

“Oh geez, you really are sick, are you, Senku.”

“Mm, no really? What gave that away?” His death glared at Gen, one eye closed as he struggled to breathe. Gen just smiled nervously, looking off to the side as he pondered.

In all actuality, he had no idea what to do at all.

He knows how to take care of people, sure, but the issue here is that he doesn't know how to take care of him. The man outright refuses to get taken care of until he's bleeding out and basically dying.

Which is what he is not doing, so basically, Gen is screwed.

“You can leave, I don't need help, just rest, maybe.” Senku said, his voice lacking that usual tone he had whenever talking. It was easy to tell that the scientist was weaker than usual.

“Oh come on! Don't be like that Senku, we are the big three, we can help you out… somehow. I can get Francoi–” Ryusui was quickly cut off by Senku.

“No need. Don't tell anyone about this, don't need the whole village to fuss over me. I can get better easily, watch.”

And despite not having any medical professionals, it was also clear to see that rest was a good medicine for this, yes, but Senku needed some kind of other medicine to help him. If they were in the modern day Gen would have maybe gone to the store and bought some type of flu medicine or cough syrup but they weren't!

Gen placed his arm in the opposite arms sleeve, looking up in thought for a moment before simply sighing.

“Oh, what are we to do now? We don't have the big-shot scientist to order us around to make any type of medicine for him.” Gen sighed, shaking his head as he smirked smugly at Senku.

Yes, he was teasing him that he was sick– but this was to side track them for a bit, okay? He needs to think of something that could help out the man.

Senku seemed to enjoy this small distraction, though and so did Ryusui.

Senku had smiled a bit, raising a brow as he turned his head to Gen before scoffing and staring up at the ceiling.

“Yup, you're all gonna die without me. Nevertheless I'm going to die because some dunces can do something as simple as making something to cure me.” He closed his eyes, relaxing his body slowly.

Gen stared for a moment, his shoulders tensing up a bit as Senku mentioned the idea of him dying. He didn't like that it was put out into the world so casually.

Ryusui on the other hand stayed quiet surprisingly. They both probably had the same thought in their minds..

Because truthfully, if Senku did end up dying they would be doomed. There's no other scientist that they know of that is willing to bring back all of humanity. There's no other man who looks out for others like he does.

There's no other Senku.

Thats the problem.

Gen’s eye twitched as he sighed, looking down at the floor and dropping his arms down to his sides.

He began to think about what might help, there are simple things like herbs that could be made into a tea, maybe someone would know the differences between poisonous herbs and non poisonous. That sounds like a job for Chrome.

“We’ll see.” Gen said, his voice faltering for just a moment.

Senku’s breathing paused for a moment, him slowly opening his eyes and looking at Gen with a look he had never seen before.

He scoffed.

“Wipe that concern off your face, idiot. No small flu is going to kill me, alright?” He sighed, coughing before going back to his daily-scheduled manual breathing now that he can't breathe for shit.

“Alright, ill leave you alone Senku. Don't forget, Francois can do just about anything, don't be afraid to call her if you need anything!!” Ryusui snapped at him before walking out of the hut.

Gen pursed his lips, slowly backing out of the hut and looking up at the sky.

Yeah.

He's gonna find a way to help him out.

It's the least he could do, after all.

So, Gen found himself strolling over to where Chrome was often– that being his hut of goods. He walked over just in time he assumes since the moment he caught an eye of the hut, he spotted the brunette going down the ladder.

Once Gen caught up to the place, he began his charade.

“Hello there, Chrome.”

“Oh! Gen, what's up? Do you need anything?”

“Well, kind of. I was wondering if you know of any herbs that might be good in teas.”

“Oh! Yeah, I know loads about that kind of stuff. Let me go get some for you.”

“Good evening, Yuzuriha!”

“Oh, hi Gen.” She smiled at him warmly, a simple conversation sparking between them. It was something that had to do with whatever she was doing and how she had been taking a break but was going to go back to work– Gen really didn't care.

Because the second he made his way to Yuzuriha, he smiled while being in the conversation with her before simply snatching a random piece of cloth without her noticing.

Sure, he could have simply asked but who cares at this point.

Not Gen.

All he cares about currently is helping Senku out with his sickness..

So that they can get back to work and get the boat ready, of course.

Truly, he doesn't care if Senku does die, nope, not a single bit. He just wants humanity to come back so life can go back the way it was– simple! Or, simpler? He isn't too sure.

He just really wants his cola back.

Too bad Senku can't make any right now since he's sick.

He waved at Yuzuriha as he walked away from her, slowly returning back to Senku.

Not before snatching a mug from Kaseki, of course!

That one he did ask for, the old man can be terrifying sometimes.

Now that Gen fully thinks about it, he didn't have to be so secretive about his whole mission, he could have honestly told the truth.

But at the same time, Senku wanted no one to know of him being sick. If he were to tell the truth, it would have broken what Senku wanted.

But why did Gen care?

Chrome would have been worried, maybe go over to Senku. Yuzuriha would probably do the same. Hell, they probably would have been able to take care of him way better than Gen could!

He sighed, rolling his eyes at his own mind. He's making this all so much harder on himself. He could go ask Francois to take care of Senku.

But.. Senku doesn't want that.

Gen simply scoffed before shaking his head, walking in with a slightly annoyed face. He often did show his annoyance when he was around Senku since he knew he wouldn't be judged– well, that's not the best word considering that Senku DEFINITELY judged him over any faces he’d make. In fact, he would literally look at him, laugh in his face before shoving more workload onto him whenever he complains.

Senkus is a pain in the ass now that Gen really thinks about it.

He walked over to Senku who still laid in the same position as before, Gen raising a brow at the sight before slowly going over and pressing the back of his hand against Senku's forehead. His brows furrowed in concern as he felt the to-warm skin.

He kept his hand there for a moment longer to make sure he wasn't going crazy with just how hot Senku felt.

That was before he saw Senku peak his eyes open, they looked groggy, but they still had that familiar spark in there.

“The hell are you doing, mentalist.” He muttered softly, him slowly sitting up and resting his back against the frame.

Gen shot his hand away as Senku sat up, him staring at Senku for a moment too long before collecting himself. He knew full well that if he didn't he was going to go out into random stutters and Senku wouldn't let him live that down at all afterwards.

“Im checking up on you.” He said simply, putting his arm in his opposite sleeve as he looked at the other.

Senku raised a brow.

“Why, you worried?”

“The flu can do a lot to a person in the stone age.”

“It won't do a lot for me.”

“And if it does?”

“It won't. I’m ten billion percent sure of it.”

Gen rolled his eyes before slowly looking to the side table.. Which is where he put everything.

“Whats this?”

“.. I made tea from herbs that Chrome recommended.” He said simply, ignoring that he was a bit embarrassed to admit it.

“..ah. okay.”

“We put sugar in it. It won't taste that bad. I tried a bit.”

“From that cup?” Senku blank faced Gen.

“What– no!”

“Mm.”

The silence remained for a moment before Senku slowly grabbed the cup, his hand shaking as he did so.

Gen stared at the shakiness of the cup, him taking a step forward and grabbing it from Senkus hands. He then pressed it against the others lips.

Senku stared at him, refusing to take a sip. It was obvious that was what he was saying behind his eyes, Gen could tell as clear as day.

“Take a sip, dammit.” Gen hushed out, rolling his eyes before letting a small smile form on his face. “Dont tell me you're embarrassed.”

Senku sighed before begrudgingly taking a sip before pushing the others hands away.

“Im no embarrassed, there's just no need for this treatment. I'm fine.” He sighed, crossing his arms. Gen could swear he saw a pout on the other's face if he squinted hard enough. That only made the split-haired man snicker, covering his mouth as he did so. It was a habit of his.

“The hell are you laughing at?”

“You're whining, Senku. I swear I can see a pout, what are you, 5?” He snickered again, watching as Senku processed the others' words. He just scoffed before uncrossing his arms.

He stuck his pinky in his ear, looking off to the side.

“Im just saying, why are you treating me like this all of a sudden, you don't have to be this worried, Gen. Usually you're the one who's complaining. Maybe our roles were swapped.”

Gen made a face at that, his hands dropping to his side as he watched Senku make a stupid smug look that he always made. He just grabbed the cup, putting it to Senkus lips again to make him shut up.

Senku smiled, staring right into Gen's eyes as he took a sip of the tea. At least this time he didn't fight it. But Gen hated the way Senku looked at him.

“You're terrible at taking care of yourself, you know. If you were healthy and what not you would be here sick. And you're always falling asleep at your workspace.” He fussed over the other, Senku only blinking at the other with this small face of annoyance.

“You're sounding like my dad. There's no need for this.” He leaned back, closing his eyes and taking in a deep breath. He probably has a headache.

“I’m just saying. If you were healthy you’d have nothing holding you back in science.”

“Hardly anything holds me back, this is a minor setback. People are still working on the boat, people are still farming, people are still living. The only thing that was put to an end was my work, which I can catch up on just as easily. Doesn't mean I wanted to stop.”

“And how long had you been working on whatever you were doing?”

“..like, 2 days straight.”

“Jesus, Senku.”

Senku shrugged, leaning forward, asking for more tea. Gen simply obliged easily, not making a big deal out of it despite having his natural resting heart race go up just a bit.

“...is that why Yuzuriha and Taiju are so used to bringing you back to bed?”

“Mhm.” He hummed softly, gulping the tea and wiping his lips with his sleeve.

Gen shook his head slowly in disappointment.

“I'm guessing you're my caretaker for today?” Senku looked at Gen.

Gen simply stared back for a moment, a feeling of hesitation washing over him the moment the other uttered those words. He pursed his lips.

“Not willingly.”

“Uh-huh. Whatever, I don't care.”

“Well, it's your fault since you don't want anyone else knowing.”

“I just don't want people fussing over me, like, you know, what you are doing now?”

“You can't even take care of yourself, be grateful!”

Senku just smiled, shrugging before looking down at the sheets he was in before closing his eyes slowly.

He really did feel like shit, hell, and he looked it too.

“..are you hot?” Gen muttered softly.

Senku opened his eyes, looking at the mentalist with this confused look.

“A bit.”

Gen put the cup down on the table near him, walking out of the hut. Once he found his way to the fountain, he put the cloth he stole from Yuzuriha and dipped it in, taking it out and wringing it before making his way back into the cabin Senku was in.

He slowly walked over to Senku, folding up the cloth before looking at the sickly man.

“Neck or forehead?”

Senku stayed quiet for a moment, staring at the piece of cloth before sighing and pointing at his forehead.

Gen stepped closer, placing a knee on the bed and creeping closer to Senku, placing the cloth on his head.

“Does that feel good? I can get another piece of cloth and put it around your neck.” Gen asked, looking at Senku, not noticing just how close they were.

Senku just stared at him before looking to the side and shrugging.

“Dont care.”

Gen gave him an annoyed look, smacking the back of his head.

“Give me an answer.”

“You treat your patients terribly.” Senku groaned, rubbing the back of his head.

“You overwork everyone.”

“For the sake of restoring humanity, what's your excuse?” He smirked at the other smugly, picking at his ear as he looked up at Gen who was towering him by this point for intimidation points.

Both of their eyes narrowed in challenged, them being completely unaware of the fact that Gen was on top of Senku.

Well, they were aware.

Senku was at least.

He didn't care, he never did care when it came to being in close contact with Gen.

Gen slowly zoned in on how close he was, quickly shooting off of the other before scoffing again.

“Go back to sleep, Senku.” Even if they were bickering, Gen could tell that Senku was feverish, and a bit delirious in what was going on.

It was a bit concerning, but at the same time, the man was sick so what was he supposed to think about it truly.

He watched as Senku slowly laid himself down, looking up at the ceiling and then at Gen.

“...thanks.”

He muttered quietly, looking off to the side awkwardly. He was never the best with emotions like said before, but it looked like he had a lot of them recently.

Maybe he got like this whenever he was sick.

“Sleep, Senku, you need it.”

“I know, shut up.” He muttered, saying on his side and curling in on himself. Gen simply smiled at the man the moment his back was faced towards him.

“Sleepwell.”

“Mm, ‘kay. Love you.” Senku muttered, already half asleep by the time he said those words.

“I love you too.” Gen replied in a simple manner, affection laying within his words without fully realizing it.

He sat down at a chair, leaning back and closing his eyes. He didn't want the other to be alone– wait a minute.

WHAT??

It was night by the time they got into this topic– how they realized their feelings for each other.

Afterall, it was mentioned several times that Senku showed little to no interest with people, nevertheless had crushes on people. So why Gen?

You’d think that Senku wouldn't fall for anyone like him– hell, for anyone at all but here they are now!

They both sat in the area where the telescope was created, the memories always being a fond one whenever they both thought about it– somewhat atleast. Senku told the tale about how he remembers thinking that he was going to die then and there, even sharing something a bit vulnerable about his dad as they sat in the dark. A small lantern being near them as they conversed, what truly gave them light was the moonlight.

It was a sight to see, truly. Senku looked good in the moonlight, and so did Gen.

“I'm honestly surprised you didn't know about how I thought about you.” Senku said suddenly.

Gens brows furrowed, him looking at Senku as his brows raised immediately after processing the statement.

“Can you blame me, truly?”

Senku simply laughed, looking down and making his hand come into contact with the floor.

“Well, you are a mentalist. You're supposed to know this kind of crap, aren't you?” He smiled, teasing as he looked at Gen, his smile slowly growing smugger as time passed.

Gen stared, his eyes squinting a bit before simply looking off to the side with irritation in his body. Senku simply continued to chuckle, looking at the night sky with this small look of admiration.

Once the silence hit fully, Gen relaxed, his gaze drifting towards Senku who was admiring the night sky.

The other was always so fascinated with it, like it was something he wanted so desperately to go into.

“You’ve always liked the night sky, haven't you, Senku? I always find you looking at the moon with this look of admiration. It's kind of irritating that the sky is the only thing that gets you like that.”

Senku glared at him for a moment before leaning back.

“My old man was an astronaut.” He stated simply. Though Gen already knew this, as his father was the founder of the village. Senku had explained the line many times that he wasn't necessarily related to the village, but was an ancestor, etc.. Gen wouldn't pay attention at times, he’ll admit.

“Yes, I know.”

“..and when I was younger I was trying to build a rocket ship. Space interests me because of the unknown properties there. That's our next goal, y'know, to go to the moon.”

Gen blinked blankly at the other. He is utterly crazy.

Maybe that's why he fell for him.

“You are insane.”

“We are building a boat and are reviving humanity. If you think going into space is crazy then I don't know where you've been these past few years. Maybe under a rock?” He rolled his eyes, looking at Gen and shoving him lightly.

Gen simply chuckled, scooting closer.

“You're like space to me.” Gen said softly after a certain amount of silence. Senku simply looked at him like he was an idiot the minute those words came out of his mouth.

“Let me explain before you call me some mean words.”

Senku just side eyed him, staying quiet, which meant that he was letting him talk.

“I don't know what's going on in your head most of the time, and you honestly come up with some azy-cray ideas most of the time but it's so fascinating. If it wasn't for your crazy ideas, I wouldn't have been on your side, I'll be honest Senku. You're a mystery to me.” He ended his sentence, looking at Senku with a soft smile.

He didn't miss the look Senku was giving him. He was a bit nervous looking but he kept his same glance at the other.

“I’m honored, I guess.”

“Thats a complement, by the way.”

“I’m aware.”

“Then why aren't you acting like it?”

Senku stared.

The silence between them was deafening, and so was the tension.

Then, suddenly, Senku scooted forward a bit before staring and giving him a small peck on the cheek.

Gen paused, his eyes growing wide as he watched Senku pull away with this awkward look.

He then smiled.

Senku sighed, looking off to the side.

“You are just adora—”

“Shut it, mentalist.”

“I have a name.”

“Don’t care.”

Then it was quiet again, Gen's hand slowly crawling over to Senku’s and slowly taking the other hand. Senku made no retaliation or move. He just let it happen.

Then, Gen felt two small squeezes.

. .

Then squeeze, long squeeze, squeeze, squeeze, long squeeze, long squeeze, long squeeze, squeeze, squeeze, squeeze, long squeeze, squeeze.

. - . . - - - . . . - .

Then long squeeze, squeeze, long squeeze, long squeeze, long squeeze, long squeeze, long squeeze, squeeze, squeeze, long squeeze.

- . - - - - - . . -

Gen stared at him for a moment, a small blush on his face forming. Who knew Senku would be so shy when it came to affection.

He smiled, leaning forward and kissing his cheek back.

“I love you too.”