Chapter Text
Leo knew he was being difficult. He could see it in the way Raph's jaw tightened, in the barely controlled frustration radiating off his oldest brother. But knowing it and stopping it were two entirely different things.
"I'm just saying," Leo continued, spinning his katana in a lazy circle, "if you'd let me lead the patrol route, we wouldn't have ended up in that construction zone with nowhere to portal out."
"The construction zone you portaled us into in the first place?" Raph's voice climbed half an octave. "Because you 'had a feeling' about a shortcut?"
They were in the lair's main living area, the others conspicuously absent. Mikey had mumbled something about pizza emergencies and vanished into the kitchen. Donnie had retreated to his lab so fast he'd left a purple-tinged blur. Even Splinter had found somewhere else to be.
Smart family. Leo should've followed their lead.
"That shortcut would've worked if—"
"If what, Leo?" Raph stepped forward, "If the building hadn't been actively being demolished? If you'd bothered to check before opening a portal? Or if you'd just stuck to the plan we all agreed on?"
There it was. The real issue. Leo could hear it thrumming under every word: Why can't you just follow the plan? Why do you always have to improvise? Why can't you be responsible?
The Shredder was gone. They'd won. But somehow Leo still felt like he was being measured against some invisible standard, constantly coming up short.
"I am the team's portal guy," Leo said, forcing his tone light even as something hot and uncomfortable coiled in his chest. "Portaling is literally my whole thing. Maybe you could trust me to know what I'm doing?"
"Trust you?" Raph's eyes widened. "Leo, I do trust you. But tonight you almost got Mikey crushed by a wrecking ball!"
"He was fine! I got him out!"
"Because Donnie grabbed him with his tech-bo! You were on the wrong side of the portal!"
Leo's grip tightened on his katana. "So what, I'm supposed to be perfect? Never make a mistake?"
"No! I just need you to take this seriously, Leo! This isn't just about you and me—this is about our brothers. It's about keeping our family safe!" Raph's voice cracked on the last word, desperation bleeding through his anger.
Leo's chest constricted. Panic rose like a tide, fear and shame threatening to choke him. Why didn't Raph understand that Leo wasn't good enough to keep their family safe? Leo was a screwup, and if he was leader, his deficits would end up destroying everything. Why couldn't Raph just be the leader again?
Lifelong defensive mechanisms sprang into place. Deflect, deflect, deflect. Leo waved his hand dismissively and broke eye contact.
"Sorry. I missed that. Can you repeat everything from... well, everything?"
The silence that followed was deafening.
Raph went very still. When he spoke, his voice was quiet in a way that was somehow worse than the yelling. "Get out."
"Raph, I didn't—"
"I said get out!" The shout echoed off the lair's walls, and Leo flinched. "Go cool off. Go do whatever it is you do. Just...not here. Not right now."
Leo wanted to apologize. Wanted to explain that the words had just tumbled out, that he didn't mean them, that he was just tired and frustrated and scared of failing them all.
Instead, he portaled away.
The night air hit Leo like a slap, cold and sharp with the bite of approaching winter. He'd ended up on a rooftop in Brooklyn, somewhere industrial and forgettable, the kind of place where the streetlights flickered more than they shone.
He sat down hard on the rooftop's edge, letting his legs dangle over the side. Below, the street was empty except for a stray cat investigating a dumpster. The city felt vast and indifferent around him.
"Smooth, Leon," he muttered to himself. "Real smooth."
The worst part was that Raph had been right. About the portal, about checking first, about all of it. Leo had been showing off, trying to prove something he couldn't even articulate to himself. And when called on it, he'd lashed out like a child.
A sound cut through his spiral of self-recrimination. Wrong sound. Not traffic, not wind, not the ambient noise of the city he'd grown up in.
Leo was on his feet in an instant, katanas drawn.
The air itself seemed to tear. Not like his portals, those were clean, precise, controllable. This was ragged, violent, reality splitting like fabric under a dull knife. Sickly green light spilled through the wound in space, and the smell of ozone, rot, and something else hit him. Something that made his hindbrain scream danger.
A shape emerged from the rift. Large. Wrong. Moving in a way that didn't match the laws of physics Leo had spent sixteen years taking for granted.
The creature stood at least eight feet tall, its form a nightmare of chitinous plates and too many joints bending at impossible angles. Its head was vaguely triangular, dominated by a cluster of eyes that gleamed with cold intelligence. But it was the tentacles that made Leo's blood run cold. Writhing appendages sprouted from its back, each one tipped with something that looked disturbingly organic. A pink, pulsing infection that seemed alive.
The rift sealed behind it with a sound like breaking glass played backward.
For a moment, Leo and the thing just stared at each other. Then it spoke, its voice a chorus of discordant tones that seemed to come from everywhere at once.
"Leonardo. The one who will seal our future. The one who must be unmade."
It lunged.
Leo portaled on instinct, appearing twenty feet to the left. His heart hammered against his ribs. How did it know his name? What did it mean, "the one who will seal our future"?
The creature's head swiveled to track him with nauseating speed. "You cannot run from destiny already written. You cannot hide from what you will become."
"Okay, cryptic much?" Leo's voice came out steadier than he felt. "How about you try that again, but in English this time? Maybe with less ominous prophecy?"
His hand moved to his phone, but the creature was faster. A tentacle lashed out, and Leo barely managed to defend himself with a slash of his katana. The severed piece of tentacle hit the rooftop and dissolved into something that looked like liquid static. His phone clattered across the concrete, spinning out of reach.
"The Krang do not forget. Do not forgive." The creature circled him, and Leo realized with growing horror that it was backing him away from the roof's edge, cutting off his escape routes. "You will destroy us in a future that must not come to pass. Therefore, you must be destroyed here and now."
Leo's mind raced. They'd fought the Foot Clan. They'd stopped the Shredder. But Krang? That wasn't—he didn't know what—
The creature struck like a snake. Leo portaled again, but this time the thing anticipated it, another tentacle already sweeping through the space where he'd appear. It caught his swords, wrenching them from his hands with brutal force and sending him tumbling across the rooftop. Leo rolled into a dazed heap and could only watch helplessly as his katanas disappeared over the ledge.
He was trapped, horrifically outmatched, and his phone was across the roof behind a monster. An ancient, primal part of him suddenly realized how much danger he was in. Realized that he might die here.
Leo's ninpo sparked in his chest at the realization. It was unclear whether it was Leo or his ancestors fueling the well of power, but either way his soul sang for him to survive. To return to his family.
The creature cocked its head, its many eyes narrowing as it watched Leo struggle to his feet, his markings flashing with signature blue light. Leo ignored the feeling of its gaze on him, the feeling of being dissected and analyzed. Instead, he reached for the well, the song in his soul, and thought of his brothers.
Mind melds were common for the Hamatos after the Shredder. Whether it was April cheerfully barging into her brothers' headspace to bully them into drinking water and eating, Raph gently brushing by to check in, or Mikey sending mental images of his artwork, the Hamatos were always connected. They just usually had to be in close proximity.
Donnie, being Donnie, had tested the mind meld's limits once they discovered the ability. In their tests, mostly involving Leo mentally screaming at Donnie from various distances, the farthest the mind meld had reached was one mile.
This time Leo was reaching across the entire city. Screaming for help. Screaming that he was sorry. Begging to be able to come home.
It felt like screaming into the void.
The monster began to laugh. An eerie crackling sound, like the scraping of metal and grinding teeth. "You are a fool if you think we will allow you to call for help. Allow you to use your ninpo." It spat the words out with disgust, leaning forward as if preparing to sprint at Leo.
"No," it growled, "we may not have enough power in this form to seal all of you. But we do have enough power to cut you off. To cut out the rot."
Leo flinched backward as the monster appeared in front of him, swinging a tentacle across his chest, etching a line of white-hot agony down his plastron. He hit the rooftop hard enough to see stars, his vision whiting out for a moment.
"Weak," the creature hissed. "So weak in this time. And yet you will grow strong enough to be our ending. Unacceptable."
Leo tried to rise, but his body wasn't cooperating. Blood, his blood, was spreading across the rooftop in a pool of alarming darkness. The creature loomed over him, tentacles raised for a killing blow.
Leo tried once again to reach out for help. But the pain was overwhelming, the burning in his chest blocking his ninpo, snuffing out the flame until all that was left was a void where his family, his soul, used to live.
This was bad. This was really, really bad.
And the only thought running through Leo's head as those tentacles descended was: I never apologized to Raph.
Then blue light exploded across his vision, and everything went sideways.
The pain came in waves. A sharp sting in his plastron acting as an unrelenting tether to consciousness. Beyond the pain, Leo registered that he was freezing, the type of cold that sank into your bones and burned from the inside out.
Where—where was he? Was he hurt? Where were his brothers?
Leo's overwhelmed brain struggled to comprehend the situation. All Leo could do was breathe through the pain and pray that whatever had done this to him wasn't nearby. That the creature—
Leo's eyes shot open, frantically scanning his surroundings for the malignant red of the creature's eyes. Wherever Leo was, it was dark. He threw a hand over his mouth to quiet his frantic breathing and strained his eyes, peering into the gloom, terrified that he would find that thing staring back.
But instead, Leo found himself in—a shack of some sort? It was a small room, abandoned and covered in dust. Two windows with shattered panes let in the barest trickle of moonlight, and Leo could make out the outline of a sturdy wooden door across the room. He jerked violently as a raindrop fell on his arm from a crack in the roof. This place looked like it hadn't been used in a decade. It was a miracle there was a roof at all.
Confusion and fear warred within him, his eyes darting around frantically as he dragged himself to the corner of the room. He left a macabre trail of blood as he sought what little comfort he could from knowing that he could keep his eyes on both the windows and door from this position.
"Okay, Leo, deep breaths," he whispered to himself. "You don't know how you got here, or where here is, or if your brothers—"
Oh god, his brothers. Was that thing after them? Could it find them? Were they safe?
Leo let out a whine, clutching his head and rocking back and forth. A distant part of him noticed the blood still pooling beneath him, but that was a small detail in the grand scheme of his panic. Leo reached into his core, searching for the spark where his family lived. But there was nothing there. No songs, no colors, just a void.
A guttural sob ripped from his throat. Where were his brothers? Even if they were far apart, he should still be able to sense them. Had that thing hurt them? Was Leo alone?
"NO!" Leo screamed, bringing a shaking, blood-slicked hand up to hit his head as if he could dislodge the thought. A memory surfaced. That creature said it could only seal Leo, that it was cutting out the rot. Maybe that meant that only Leo had been separated from the ninpo? Leo hugged himself as he continued to rock, praying desperately that was the case.
All Leo truly knew was that he was alone for the first time in his life. He wished he could be heroic in that moment, drag himself to his feet and rush out to find his family. But Leo wasn't a hero. He was a screwup. He was the rot.
All Leo could do was cry, slumped in a corner, listening to the rain drumming against the roof above his head and feeling the pool of blood beneath him grow. As his eyes slipped closed, exhaustion dragging him under, he prayed that if he died he would be allowed to join the ancestors.
Or had he been cut out from that too?
Donnie gazed at his latest creation and leaned back with a satisfied hum. Mikey had requested a projector for his room—a simple task for a genius like him—and he'd spent the last few hours coding and installing custom hardware to make it perfect. Whether his little brother wanted to watch shows, create art, or create chaos, this projector would adapt to his needs.
Hmmm, he did need to verify that the built-in sound system was functional, though. Which meant taking off his headphones.
Donnie grimaced at the thought. He'd retreated into the soothing beats of his EDM playlist when Raph and Leo started shouting at each other, and he didn't want to remove his headphones before the fight ended. Donnie examined the door to his lab warily, as if he could see the impact of the argument through solid steel. Leo hadn't barged in yet to rant, so he suspected the argument was still occurring.
Donnie spun his chair around, kicked off the desk, and wheeled over to his computer bank, pulling up the various security cameras around the lair. The cameras were of course contained to the common areas, but Donnie did have shots of every entrance and exit, so he could theoretically gather the necessary information for this situation.
His eyes narrowed in confusion as he opened the atrium's live feed and found it empty. Donnie clicked rapidly as he cycled through the camera system. Mikey was in the kitchen, Raph was in the dojo, Splinter was watching TV.
Hmmm, Leo must be in his room. But if the fight was over, why didn't he come to Donnie's lab for his usual soliloquy on the injustices of their older brother? It was suspicious, to say the least.
It was a mystery to be solved.
Donnie pulled his headphones off swiftly and slid out of his chair, laser-focused on his new mission. The lab doors opened with a pleasant whir, which made it all the more surprising when Donnie was almost taken out by his little brother passing by.
"Oh-mi-gosh!" Mikey exclaimed, wobbling dangerously as he tried to balance the plate of cookies he was holding after running into Donnie.
Two arms emerged from Donnie's battle shell, one steadying the box turtle and the other steadying the plate. "And what has you in such a rush, Michael?" Donnie questioned. The chrome arms gave Mikey a gentle pat on the head before retreating into the battle shell.
Mikey grinned at the action and held the plate of cookies up to Donnie's face. "I'm bringing cookies to Leo! You can have some if you want, though!"
Donnie assessed the treats. Snickerdoodles—Leo's favorite. The situation must be more dire than Donnie had originally thought. "Ah, yes, that is quite serendipitous. I was just going to find our resident dumb-dumb myself." Donnie began to walk forward, Mikey falling in line beside him. "I take it Leo's locked himself in his room?"
Mikey nodded enthusiastically, his plate of cookies bouncing with the movement. "Yep! Raph's in the dojo engaging in the Dr. Feelings-approved coping skill of exercise, so Leo's going to be my first victim today."
Mikey's hands clenched dangerously around the rim of the plate, the ceramic groaning nervously as Mikey's expression hardened. "I need the cookies to get me in the door so Dr. Delicate Touch can have a little conversation with Leo. Dr. Delicate Touch has had it up to here with that boy's behavior."
Donnie hummed in agreement with Mikey's sentiment, but still sent a silent prayer to Leo, wishing him luck once they arrived at the slider's door.
"Oh, Leoooo," Mikey sang brightly. "Donnie and I are here for a check-in. Can you let us in, please?"
Leo's door stayed silent. Not even the usual rustle of Leo crawling under his bed to hide from the consequences of his actions.
"We are here for a purely supportive visit, and in no way want to discuss your antagonistic attitud—" Mikey elbowed Donnie in the side with a glare.
The door continued to stay silent.
"Welp, we tried it the easy way!" Mikey said as he set the plate on the floor, backed up, and kicked the door open with a flying leap. "Boy, you better get your butt out here so we can talk, or else—"
Mikey paused mid-rant and gazed around the room. Leo wasn't there. In fact, based on the made bed and tidy comics, it looked like Leo hadn't been there since they'd arrived home that afternoon. Donnie peered under the bed just in case, but no Leo.
That was... odd.
Mikey was gazing around the room uncertainly. He looked at Donnie questioningly. "Do you know where Leo is? I checked the whole lair, so I just assumed he was in here..."
"Worry not, dear brother. It is a simple enough question to answer through the power of—" Donnie whipped out his phone triumphantly, "—technology!"
Mikey oohed appreciatively at Donnie's display, crowding in close to see his phone screen. "I simply have to pull up the Donnie Device Tracker, locate Leo's phone, and therefore locate Leo," Donnie said proudly.
Mikey paused. "I'm sorry, did you just say you're tracking our phones?"
Donnie felt a chill run down his spine. "No..." he said suspiciously.
Mikey's eyes narrowed, but his smile stayed in place. "I hope you know that once Leo is squared away, you and I are going to have a little talk."
"Anyways! Look, Leo's out of the lair. Let's focus on that instead!" Donnie declared, pointing frantically at his phone screen in a desperate bid to redirect Mikey's wrath.
"WHAT!"
Mikey and Donnie jumped, clutching each other in panic as Raph's yell echoed throughout the room.
Raph rushed in, ignoring his younger brothers' surprise, and yanked Donnie's phone out of his hand. "Leo should've been back ages ago! What is he thinking?" Raph growled, shaking the phone as if he could also shake Leo in the process.
An anxious part of Donnie settled at his older brother's statement. "So you knew Leo was leaving the lair?" Donnie asked distractedly, visually tracking his phone's movement, waiting for the perfect moment to grab it back.
Raph let out a huff of frustration and put a hand up to his face, as if the mere reminder of Leo was too much to think about. Ah, perfect! Donnie swiftly rescued his phone from Raph's grasp while his older brother blinded himself.
"Yeah, I told him to go cool off a bit after our... y'know." Raph grumbled. "But he should've been back by now."
Donnie accepted a cleaning cloth from one of the arms of his battle shell and began wiping off his phone screen. "Well, how about we just call him?"
"Great idea!" Raph ripped the phone out of Donnie's hands again and clicked on Leo's contact information.
"Ah—Raph! I just cleaned that!" Raph put a hand out to ward off Donnie's desperate attempts to defend his poor phone.
"Just give me one minute, Donnie! Leo won't pick up a call from me, but he always picks up for you."
Click. "The number you are trying to reach is not available. Please try again later."
The room stilled, a stunned silence falling over the brothers. That...that wasn't right. Leo always picked up Donnie's calls.
Donnie yanked his phone out of Raph's slack grip and redialed. Click. "The number you are trying to reach—"
He redialed again. Click. "The number—"
"Donnie." Raph's voice had gone quiet, dangerous in its steadiness. "Where is he?"
Donnie's fingers flew across his screen, pulling up the tracker map. A blue dot pulsed on the screen, stationary in Brooklyn. "According to the GPS, his phone is..." Donnie zoomed in, his stomach dropping. "On a rooftop. Industrial district. He's been there for—" He checked the timestamp. "Three hours and 13 minutes."
"That's not right," Mikey said softly, his earlier bravado completely gone. "Leo doesn't just... sit somewhere. Not when he's upset."
Raph was already moving, grabbing his sai from his belt. "We're going. Now."
Donnie didn't argue. He sent the coordinates to everyone's phones and followed Raph out of the room, Mikey close behind. The cookies sat abandoned on Leo's floor, forgotten.
The rooftop seemed innocuous from a distance. Why Leo had chosen that particular rooftop was beyond Donnie, but he wasn’t overly concerned as he climbed the ladder to go retrieve his twin.
Then the scent hit him.
The roof reeked of ozone and something worse—something organic and wrong that made Donnie's senses go haywire the moment he hauled himself to the top of the industrial building.
"What is that smell?" Mikey whispered, pressing a hand over his nose.
Donnie was already scanning, his goggles lighting up as data streamed across the lenses. "Chemical composition is... bizarre. Organic compounds I've never seen before, trace radiation, and—" He stopped, his heart lurching. "Blood."
Raph was ahead of them, frozen in place. "Guys."
The rooftop was a war zone. Scorch marks scarred the concrete in erratic patterns. Deep gouges carved through the surface like something with claws had tried to tear the roof apart. And there, near the edge, was a dark stain that could only be one thing.
"No, no, no." Mikey was shaking his head, backing away. "That's not—Leo's fine. He has to be fine."
Donnie's scanner beeped insistently. He followed its direction with numb compliance, walking toward the center of the destruction. There, partially dissolved into the gouges, was a piece of... something. Wrong.
A pulsing, writhing infection that sent shivers of disgust down Donnie’s spine. He watched in horror as the piece of—Flesh? Machine? Infection?—seemed to shift, like it was reaching towards them. Donnie forced himself not to act on instinct, twitching as he fought the urge to run away and take his brothers with him. He leveled his tech bo, ignoring his shaking hands and pounding heart, and shot a containment field over the piece of flesh. A purple orb materialized around the sample, which writhed and twitched frantically before collapsing into an eerie stillness.
"Donnie, what is that?" Raph's voice was strained.
"I don't know." The admission tasted like ash. "I've never seen anything like this. The cellular structure is—it's not from Earth. It's not from anywhere in our known taxonomy." Donnie commanded the containment field to stay floating in the middle of the roof, a part of him too scared to get closer to it.
Mikey made a small, broken sound, backing away from the monstrous sight, trying to search the rooftop without taking his eyes off it. "His phone. Where's his phone?"
They found it near the edge of the rooftop, screen shattered, casing cracked. After some searching they also found Leo’s katanas abandoned on the sidewalk below.
Raph picked them up with shaking hands. "He wouldn't leave these. He wouldn't—not unless—"
"There's no body." Donnie said it quickly, desperately, even as his mind raced through increasingly terrible scenarios. "No body means he could still be—we don't know what happened here."
But the blood. There was so much blood. A trail of it leading to the roof's edge before it just...stopped. As if Leo had been dragged to the precipice and then vanished into thin air.
Mikey was crying now, silent tears streaming down his face as he stared at the bloodstain. "We have to find him. Donnie, you can track him, right? You can find him?"
Donnie wanted to say yes. Wanted to pull out some brilliant solution, some piece of tech that would lead them straight to Leo. But he looked at his scanner, at the impossible readings, at the evidence of something so far beyond their experience that he didn't even have a framework to begin understanding it.
"I'll try," he said instead, and hoped it would be enough.
Raph was still holding Leo's katanas, clutching them like a lifeline. When he spoke, his voice was raw. "This is my fault. I told him to leave. I—"
"No." Mikey's voice cut through, surprising them both with its firmness. "We're not doing that. We're not falling apart. We're going to find Leo, and we're going to bring him home."
Donnie nodded, forcing his mind into gear. Analysis. Data. Solutions. "I'll collect samples, scan everything. Whatever did this left traces. We can—we will figure this out."
But as he knelt down to gather evidence, his hands wouldn't stop shaking. And the question none of them were asking hung heavy in the air.
What if they were already too late?