Chapter Text
Donatello rubbed his eyes harshly, clearing up his vision. He was starting to make a lot of dumb mistakes, a sign that he needed to make himself some stronger coffee.
It would work this time, it had to. He had double-checked everything, just to be sure. Donatello put the Kraang device on the floor –careful of the mess of tech awkwardly welded together he'd used to replace one of the missing parts– and manually restarted it.
The device started vibrating, and then slowly rose from the floor. Hope swelled in Donnie's chest, but he didn't call out to his brothers, he'd already given them too many false hopes on his last unsuccessful attempts.
He was right not to: thick, nose-stinging smoke started rising from the device. The smoke detector activated and water started pouring on everything, the sharp scream of the smoke alarm ringing in the lab.
The disappointment left him dizzy and he slumped on his chair, his head heavy with that same headache that kept coming and going since the beginning of the week.
Raphael was the first to burst in, red-faced and covered in sweat, his eyes darting everywhere before landing on the device. It was still hovering and still smoking, now with an additional grinding sound adding to the ambient din.
Leo arrived second, just in time to see the device tearing a portal in the middle of the lab.
Donnie jumped to his feet, he’d made it!
Had the portal been undamaged, it would have reached the ground. But it was small and unstable, flickering and shifting in size and shape, requiring a solid jump to reach. Donatello scrambled for filtration units. They needed to be quick, he didn’t know how long it would hold and it was already starting to shrink.
They were about to jump in when huge, scaly hands came in from Dimension-X and gripped the sides of the portal, pushing it wider until Leatherhead’s large snout came out, then all of him.
He was alone, why was he alone?!
“Where’s Mikey?” Leo’s voice was just as urgent and panicked as Donatello felt.
Leatherhead walked away from the portal, he was coughing and it seemed like he was going to hurl on the ground. Thankfully it didn’t last and he turned around to stare at the portal, without answering their question. From the corner of his eye, Donatello saw Leo hold back a furious Raphael.
“Leatherhead!” Inquired Leo, louder over the sound of the room’s global commotion.
Donatello didn’t have any more patience than Raphael, if Mikey wasn’t here, then Donnie would have to go get him himself before the portal closed. He grabbed the filtration units and threw two to his brothers.
“Ah!” Michelangelo stumbled out of the portal, falling face-first into the ground with a Bam and a “Uk–”.
Donatello stared. Mikey was here, it wasn't a dream this time, his little brother was home.
“Mikey!” Raph was first by his side, followed closely by Leo. Together they helped him sit up. He was as pale as a sheet, staring at his brothers with big wet eyes, not saying anything.
Mikey shouldn’t be so pale and silent, something was wrong. Donatello pushed Raphael out of the way, ignoring his protests. Mikey’s hands were clammy and his breathing was… “He’s not breathing!”
Immediately, Raphael and Leonardo grabbed firmly each one of Mikey’s arms, as if it was going to do anything. His filtration unit was nowhere to be found, Mikey couldn’t have been in there without it, where was his filtration unit!?
Mikey shook his arms out of his brothers’ hold before firmly thumping his plastron a couple of times. He grunted and then he started coughing violently, curling up on himself, his body shaking with spasms as he struggled to breathe.
"Donnie, what's happening to him?" Leo’s voice was tight with worry.
The answer was a short, nearly growled, “I don’t know.” His eyes didn’t leave his brother's shaking form. Mikey was on earth, he shouldn’t have any problem breathing here. Plus he wasn’t not breathing, he was– he was–
“Dimension-X’s atmosphere is much thicker than earth’s. The transition can be a shock if his anatomy isn’t made for it.” Leatherhead was keeping his huge form out of the way, but he was still watching anxiously.
Now that he knew what to look for, Donatello could see some faint pinkish smoke escaping Mikey's mouth. His mind immediately conjured everything he knew about liquid breathing and all the disastrous effects the past attempts in medical history had led to. Mikey’s lungs were probably still full of the stuff, he needed to cough it all out to breathe better. Donnie gritted his teeth. It was unfair, the first time seeing his brother in three months and he was utterly incapable of helping him.
He shuddered, the filtration units were in case Dimension-X's atmosphere was toxic. He’d never been happier to be wrong, Mikey would have been dead by now if he wasn’t.
Mikey’s body was wracked with uncontrollable coughs and gasps, one hand holding tightly his belly and the other clutching Raphael’s knee, leaving bloody crescent marks where his nails pierced the skin.
Raph didn’t seem to even realize, his face was livid and his hands hovered uselessly over Mikey, unsure of what to do. Leo didn’t have such hesitations, he started rubbing his shell, trying to offer some small measure of comfort.
Donatello slipped his arm under Michelangelo's tight form, placing his hand on his chest, frantically feeling for the state of his brother’s lungs. With the spasms following each ragged breath, Donatello could feel the rattle from the thicker substance obstructing his lungs. He put his second hand on the back of Mikey’s neck, he needed to calm down, panic could only worsen the breathing problem. “I know it’s hard Mikey, but you need to slow your respiration.”
Michelangelo did, he tried. His coughs turned into harsh, guttural moans and his chest quivered painfully under Donnie's trembling fingers. It was a sign that Mikey was getting more air, Donatello knew it, but it was distressing anyway.
Leo leaned down, gathering Mikey in his arms, then against his chest. Mikey’s face was contorted with panic, his eyes wide and unfocused, big fat tears streaming down his face.
Raphael grabbed Mikey's arm again, squeezing reassuringly, looking up at Donatello expectantly.
Donatello was going over a mental list of everything that could help, but there wasn't much to do. He grabbed Michelangelo's other hand, "You're doing great Mikey, here, you're already breathing better, can you feel it?"
Mikey nodded slightly, his chest heaving with each labored inspiration, the spasms lessening in intensity, a deep wheezing sound escaping from his throat.
Finally, he slumped back against Leonardo, exhausted and weak. When he spoke, his voice was hoarse and scratchy, "Ha, sorry for the scare." It was the most beautiful sound in the world.
Donatello collapsed on Mikey, crushing his baby brother in the tightest embrace possible. Mikey hugged back, one of his hands scratching lightly his scutes. Donnie could have passed out from relief, for the first time in three months, everything was alright.
Raphael made space for himself in the family hug. His embrace was much more forceful and he mushed his cheek against Mikey's head as he said, "You're never getting out of my sight ever again, do you hear me? If you do that again, I’ll beat the crap out of you."
This made Mikey giggle, "Aww, missed you too!"
Leo didn't say anything, seemingly content with all three of his brothers in his arms. He probably didn't have any more courage to leave than Donatello because he turned toward Leatherhead and asked, "Could you go retrieve Sensei? He must be in his room."
Leatherhead nodded before leaving the lab.
Donatello would have stayed right there and never moved ever again, but Mikey started to push them off. Leonardo was pinned under his siblings and Raphael didn't budge, the only one to comply was Donnie. Thankfully, Mikey kept a firm grip on his shoulder, holding him at arm’s length. Like that, they could get a good look at each other.
Mikey was missing his bandana and he seemed tired despite the lack of dark circles under his eyes. He hadn't actually been pale from shock when he arrived, his skin was washed-out and discolored with a slightly grayish tint.
"God, Dee, you look like shit! What happened to you?"
It was so ridiculous Donnie couldn’t help but chuckle, “I’m not the one that got stuck in a foreign dimension full of enemies for three months. I’m more worried about you.” And then he dragged Mikey to the examination table, ignoring the protests of his two older siblings.
Mikey didn’t protest, and he automatically closed his hand around the plastic cup when Don handed him one with a curt, “Spit in there.” before starting to gather his equipment for a global checkup.
Mikey didn’t ask any questions, it was Splinter who wondered, “What for?”
Donatello hadn’t even noticed that Leatherhead had come back with their Sensei. “If Dimension-X’s air is that thick, then there will be some of it still in there, I’m going to analyze it, just to be safe.”
When he turned back toward Mikey, he was sandwiched between Leo and Raph, staring at the empty cup and not saying anything.
Leo nudged him, “Hey, you alright?”
But Michelangelo ignored his question, turning his attention toward Leatherhead, “How long were you in Dimension-X?” which was a stupid question, they already knew the answer. It was what? A year? Maybe more?
But instead Leatherhead answered, “It’s been more than ten years.”
Raphael was the first to react, “No, you left last year. It was months ago, not years.” before being chastised by both Leo and Mikey for being rude.
Donatello frowned. Leatherhead did look older, maybe. But then it would mean… His brain was already spitting-out hypothesis after hypothesis. They were all bad, either because they were very unlikely or because he really didn’t like what it could mean.
Mikey spat in the cup and handed it to him, silent. Donnie put it away before starting his examination, he wanted to be done with Mikey before checking Leatherhead for signs of experiments that could have led to something like that. It was one of the Kraangs' experiments, it had to be.
Mikey went along with the examination without making a fuss like he usually did. It was unnerving. Leo and Raph didn’t want to get farther from Mikey than they had to. Donatello understood, really, having Mikey here still felt surreal. But it didn’t make the examination easier.
He’d grown by a few centimeters, there were a few new scars, a slight loss of muscle mass and his pale complexion. Some of Dimension-X’s atmosphere probably remained in his lungs but it would be cleared away with breathing exercise and the next few training sessions. Donatello sighed with relief, there was nothing incredibly worrying.
Once he was done, he turned to Leatherhead, “Your turn now, if one of the Kraangs' experiments turned those months into years then it may have done something else.” But Leatherhead drew back, clearly against the idea. It was understandable, especially after what he went through, but still–
Mikey slid down from the table, followed by Raph who refused to let go of his arm, “There’s no need, it’s not an experiment. Time is just different in Dimension-X.”
Ah, a temporal differential then. That was crazy, but that meant… “How long was it for you?”
Mikey tilted his head to the side, thinking. “Probably around three years.”
Three years?!
“Anyway, I’m starving. I’m going to make spaghetti, who wants some? Leatherhead, will you eat with us?”
And he fled the lab.