Chapter Text
Day 1- 10:00 pm
When Donnie suggested that he and Leon take a twins-only trip out of America someday, he'd meant somewhere like Tahiti or Italy.
He had not meant an entirely different dimension.
Street signs they’d spotted while looking around still read New York, but everything else was wrong. The city felt too quiet, drained of colour and background noise. It was strange seeing a lack of glowing billboards lighting up the sky, no traffic roaring all hours of the day and night. In the past hour, Donnie counted maybe two or three people total.
But the real giveaway was the absence of mystics; he scanned the area with his goggles, and there was absolutely nothing.
So yeah, they had somehow found themselves in a different dimension.
The worst part? They didn't even know how they'd gotten here since Leon had opened a portal meant to drop them into Run of the Mill, but instead of the familiar restaurant, they'd stepped out onto an unfamiliar rooftop. Neither of them realized something was wrong until the portal behind them snapped shut and now Leon couldn't seem to get it to reopen to a place in their own dimension. Each portal spat them out somewhere else in the same uncanny New York: another rooftop, another empty street, another stretch of this dull, lifeless city.
By the tenth jump, they gave up on Leon’s portals.
Now they sat on the edge of the last rooftop they'd landed on, Donnie's legs dangling over the side as he hunched over his tech gauntlet. Behind him, Leon paced back and forth, frustration rolling off him in waves, when the sound of footsteps pulled them from their thoughts.
Donnie whipped around, while Leon stopped pacing; they both spotted four figures that stood overlooking them, their silhouettes cloaked in shadow, surrounding them.
Each of them had eyes that glowed an unnatural white in the gloom.
Donnie rose and moved to be next to Leon to face the newcomers. "Leon?"
"Yeah," Leon muttered, hands already drifting toward his swords, "I see them."
One of the figures stepped forward, still hidden in the dark, two swords held in their own hands.
"Who are you?" The stranger demanded. "And what are you doing here?"
Leon forced a grin. "Okay, before anyone starts swinging. Hi. We're... very lost."
"How lost?" The tallest one asked blatantly. "Because your energy signatures aren't from anything on our Earth."
The second shortest of the figures dropped into a combat stance. "Leo, I say we stop asking questions and just fight them!"
"Wait... what? I’m confused." Leon’s brows knitted. "I don’t want to fight! I don't even know who you are."
"Is your name Leo?" The second shortest scoffed. "I wasn't talking to you."
"It actually is Leo, thank you very much." Leon shot back, a touch defensive.
“I think I know what’s happened...” Donnie's eyes widened as the pieces snapped together; the spotlights in his battle shell flared to life, washing the rooftop in a stark white.
Four other turtles stood revealed, wearing familiar mask colours; they reacted instantly as the sudden light stripped away the shadows.
Red lunged without warning as he was startled by the sudden brightness, his Sai snapping toward Donnie's jaw.
Donnie barely had time to react; his bo materialized out of his ninpo instinctively, pulling it up between the Sai and his throat just in time to catch the blades, the impact shuddering through his arms as steel rang against mystic wood.
The moment Red attacked, the rest followed; Blue blurred into motion, swords flashing as he closed the distance.
Before Blue’s katanas could connect, Leon threw one sword and vanished in a burst of light, reappearing behind him in a crackle of energy. Blue spun, eyes widening for half a heartbeat before hardening and swinging again.
Donnie blocked Purple’s bo with a shield made of ninpo, and pixelated sparks skittered as the weapon hit his construct.
Red roared and charged again, angling for Donnie's back, but he didn't get far before Leon jumped out of a portal directly in front of him, blades crossed, blocking the hit inches from Donnie.
Red blinked. "What-"
Leon vanished into another portal and reappeared above him. He came down hard, striking with the flat of his blades and driving Red to one knee before flipping away and landing in a low, ready stance causing Red to snarl and surge forward again, refusing to stay down as rage seethed. The turtle slashed at Leon, blades barely brushing past as Leon kept teleporting, his movements a blur of light.
"Stop moving!" Red roared, lunging with a wide, sweeping strike.
Leon blinked out and reappeared to Red's left.
Red twisted and slashed, only for Leon to once again show up on his right.
Red spun, breath coming fast, frustration boiling over, and Leon warped directly behind him, aiming a shot when Blue suddenly struck without warning into him, the impact rattling through his shell.
Leon backpedalled, teleporting quickly, only for Blue to find him again instantly; his knee twinged as he stepped on it, causing him to stumble.
Blue’s blade slipped past Leon's guard and slashed across his shoulder. Leon threw a sword and, in a blink, was near Donnie; his feet skidded against the concrete when he caught himself, hissing as he held the wound.
Donnie's heart stuttered at the sight of it, the cut across Leon's shoulder, the dark smear of blood against green skin.
No.
Not again.
His hindbrain screamed, a cold, panicked spike: your twin is hurt; you need to end the fight before it gets worse, and the decision snapped into place before he could second-guess it.
This had to end now.
Orange exploded into the space between them, spinning his nunchucks. Donnie swore and slammed his staff down, causing a translucent barrier to snap into place just as Orange's strike hit, the impact sending a visible ripple across the shield. Orange bounced off it with a startled whoa, flipping backward and landing lightly on his feet, laughter spilling out of him.
"Oh, that is cool-"
He didn't get to finish the sentence, as a sudden impact knocked him flat onto his carapace; he barely had time to blink before a foot came down hard on his chest, pinning him to the rooftop. Purple light surged brighter as Donnie stood over him, eyes sharp and blazing. Behind him, the constructs at his back shifted into half a dozen hard light cannons, all of them aimed directly at Orange.
"Mikey!" The other three shouted at once, terrified for their little brother.
"EVERYONE STOP!" Donnie shouted, his voice cutting through the chaos, knuckles whitening as his grip tightened on his staff. "Can we please stop trying to kill each other long enough to acknowledge that if we wanted to hurt you, this fight would already be over?"
"Let him go!" Blue barked, stepping forward, looking for a way to disarm the threat.
"Not until you hear us out!" Donnie snapped back and then pointed to each of them. "Orange, Michelangelo. Red, Raphael. Purple, Donatello. And Blue." He stated, pointing to the last one. "Leonardo."
"How do you know our names?" Leo stepped forward, his grip tightening on his swords.
“Because we’re you from an alternate dimension!" Donnie cried out.
"Alternate dimension?" The other purple masked turtle echoed with disbelief.
Donnie tapped his chest. "My name is also Donatello." Then he gestured to Leon beside him. "And this is Leonardo."
"This isn't funny!" Raph snarled. "Who are you really?"
"I just told you!" Donnie shot back.
Raph took another step, eyes blazing. "Do you think we’re fools? Do you even know how insane that sounds?" He demanded. "You’re just saying that so you can gain our trust and then stab us in the shells! Who's to say you aren't with the Foot, or the Kraang?"
Leon’s eyes widened while Donnie’s heart dropped to his stomach. They turned toward each other at the same time, horror laid bare across their faces.
"The... Krang?" Leon stammered. "They're here?"
Raph frowned. "Of course they're here." He said with a scoff. "They've been here for years. Why? Got a problem with them?"
Leon and Donnie didn't answer; a silent exchange passed between them in a single glance, feeling the shared terror of a day where they'd almost lost everything.
"H-How?" Leon finally asked.
"How what?" Raphael snapped back.
Leon opened and closed his mouth, unable to get the words out.
"Uh... what's with the looks, dudes?" Mikey asked, trying for light humour but missing the mark. "You guys are acting like he just said the world was ending. They're just the Kraang. I mean, yeah, there might be thousands of them in New York, but they're not that scary."
"Thousands?" Leon gasped. "Thousands? How is your planet still standing? We fought three and barely escaped with our lives!"
The constructs at Donnie's back flared brighter as memories and fear invaded his mind, his control began to slip, the cannons whined, power screaming as it built up.
The others shouted at once, their frantic voices overlapping.
"Stop!"
"Hey! Stand down!"
"Please! Don't hurt him!"
Donnie barely heard them; all he could think of were the blue, pink and purple tendrils, slick and writhing, stabbing into his shell, into his neck and arms, forcing their way into his nervous system. He could feel them again, invasive and cold, threading through his thoughts.
And then the screaming static and the violent snap of the connection to his twin as a portal shut.
He looked down when sharp nails suddenly dug into his ankle. A version of his little brother was pinned under his foot, eyes wide and glassy with terror, staring up at him like Donnie was the monster.
Donnie's breath hitched hard.
No, no, no...
Donnie gasped, "I'm sorry!" and the constructs dissolved as he stumbled away. "Sorry! I’m sorry! I didn't mean to- I can't-"
Mikey scrambled free, heart hammering, and his brothers were on him instantly, arms wrapping tight around his shoulders and shell, pushing him behind them.
Leon’s vision wavered, and his ears began to ring as unwanted thoughts invaded his mind; his eyes flitted over the rooftop, searching for any sign of the red eye of a mechanical terror, listening for the squelch of pink limbs.
His family? Where were they? Donnie was just here, wasn’t he? He didn’t recognize anything around him.
Leon made a broken sound as his swords slipped from his fingers and clattered to the floor; he staggered a step, then fell to his knees, curling in on himself. The sound snapped Donnie's head around; for a split second, terror punched through him. He dashed across the concrete and tumbled to the ground to grab onto Leon by the forearms, instinctively putting up a shield bubble around them.
"Leon? Leon, look at me," Donnie cupped Leon’s face, desperate to make sure his twin was ok. "You're ok, I’m right here; you’re safe- you- you're here."
Leon sucked in a breath as Donnie pulled Leon into an embrace, his hands automatically covering the healed cracks on the slider’s shell, pulling him closer while Leon’s hands came up automatically as he clutched at his twin like a lifeline. Donnie whispered into his ear, repeating again and again as if trying to believe the words himself, "I've got you. I've got you, you're not gone. You're not- you're here, say something, please-"
Across the rooftop, Don’s mind was already racing as he looked at the two unfamiliar mutants; they were giving off energy signatures that didn't match anything native to this world, wore mask colours that mirrored theirs, used identical weapons, and the fact that they knew their names and knew about the Kraang.
But a different Krang.
There were too many coincidences.
"I'm starting to believe your story." Don stepped forward. "It sounds completely insane, but given the available data, it's... possible."
"Don!" Leo snapped, moving toward him.
Don didn't look back. "I said, starting." He replied. "I'm going to call April; she can use her abilities to know if they're telling the truth." He turned away, already lifting his t-phone to his ear.
Raph crossed his arms, scowling, eyes never leaving the two strangers. He positioned himself just a little in front of Mikey without even thinking about it.
Mikey peeked out from behind him, forcing a crooked grin. "So, uh... if she says they're telling the truth." He started. "Does that mean they're, like... our brothers too?"
The joke died when he actually looked at them.
Donnie’s markings glowed as he held the shield around both of them; his eyes were squeezed shut as he curled around Leon in a protective hold, and Leon who held onto Donnie just as tight.
They were scared.
Mikey's grin vanished completely.
"...Oh."
Whatever these two were, they weren't here to fight, and they definitely weren't okay at the moment. Mikey's expression softened as he stepped closer, moving slowly before he knelt down in front of the shield, keeping his hands visible. "Hey, are... you guys okay?"
Leon blinked, clearly taken aback by the kindness. "What?"
Mikey gave a small, apologetic shrug. "I- I'm sorry that we scared you."
"Mikey, don't apologize!" Raph barked, still bristling, jaw tight, fists clenched. "They just threatened to blow you up!"
Mikey glanced back over his shoulder at Raph; his brother's stance screamed with readiness to fight and protect.
"Yeah..." Mikey spoke. “But that's because we attacked first, and they're not doing that now."
He turned back to the newcomers, letting them see he meant no harm.
Donnie let out a shaky chuckle. "Even in another universe... Mikey always manages to see the best in people."
Mikey smiled at that. "Until April gets here and does her, uh... mind magic thing, nobody's going to fight, so how about we all just... chill for now?"
Leo hesitated, fingers tightening once more around the hilts of his swords before he sheathed them across his back.
From across the roof, Don stopped pacing. "April will be here in about five minutes." He called out.
Mikey gave a thumbs up.
Raph exhaled sharply through his nose, finally loosening his stance, shoulders dropping fractionally, though his eyes never strayed from the strangers.
"I'm sorry, Mikey..." Donnie spoke after a few moments. "I wasn't going to hurt you. I promise."
Mikey's eyes lit up, and a grin spread across his face as he said, "I know, you really didn't look like you wanted to."
Donnie held Leon tighter and gave Mikey a gentle nod.
A few minutes later, something thudded onto the roof, and every head snapped up as April stepped into view.
Don froze mid-pace, then broke into a relieved grin. "Hey April!"
Her gaze swept the area, taking in the glowing shield and the unfamiliar mutant turtles.
"...Okay." She said slowly. "Who... are they?"
Mikey waved enthusiastically from the floor. "Hi, April! They might be our brothers!"
April blinked. "What?"
"They say they're from an alternate dimension," Don explained, stepping forward. "And they're claiming to be versions of Leo and me from that universe."
"That's why I called you." Don continued. "I need you to use your powers and tell us if they're actually telling the truth."
April walked over to the shield and lifted a hand to her temple, exhaling slowly as she focused on the two strangers, letting her powers sweep over them.
The rooftop held its breath.
April lowered her hand after a few moments; her gaze met Don's, shock evident across her face. "They're telling the truth; they're... actually from an alternate dimension."
Donnie finally released the shield.
Mikey didn't hesitate; he leapt forward, wrapping both Donnie and Leon in a tight, enthusiastic hug without warning.
"We have more family, dudes! This is amazing!" Mikey cheered, voice full of pure joy.
Raph’s mouth fell open. "You've gotta be kidding me."
Leo rubbed the back of his neck, still trying to process everything. "So... they're really us?"
Don’s eyes were wide with a mixture of excitement and disbelief as he ran over to the two. "I've had theories about the multiverse for years, but I never thought it could actually be real! How did you travel here?"
Donnie forced himself up and away from the hug, carefully moving Leon and Mikey aside. “That’s the problem: we don’t know. Nardo opened a portal that should’ve taken us somewhere in our dimension.” His fingers started scratching at his forearm; Leon was on his feet in an instant, catching his hand before he could hurt himself. “Somehow... We ended up here instead.”
“I have about a hundred follow up questions for you.” Don’s brain was already sprinting ahead, lining up theories faster than he could say them.
Leo placed a hand on Don’s shoulder to stop him. “How about we head back to the lair?” He suggested instead. “We can order some pizza... as an apology for attacking you.” A faint, sheepish smile crossed his face. “You both sound like you’ve had a rough day, and we shouldn’t risk our enemies running into you.”
“That sounds great.” Leon smiled, clearly relieved.
Leo led the way toward the edge of the roof, the others trailed behind him as the night air tugged faintly at their gear. Leon strayed and retrieved his swords from the ground, turning them once in his hands out of habit before sliding them smoothly back into their sheaths, the familiar weight settling across his back as he jogged to catch up.