Archive of Our Own ^beta

Chapter Text

Mikey winks at Casey, a warm smile across his lips full of the familial love the human had gotten to know from all the turtles. The mystic warrior rips the portal open the rest of the way with his little remaining life force, his body ripping apart and disintegrating right in front of the teen and older brother. The little glints of his dusty remains shine in the light of the portal, then scatters away through the wind.

Casey feels his eyes burn with tears, his air feeling like it’s been stolen from his lungs. Beside him, the Sensei sighs resigned at the loss of his last brother, he smiles despite it… his little brother had always been stronger than any of them gave him credit for as a kid. 
“You ready?” Casey knew it wasn't a question, it was a command from his teacher. He nodded as he swallowed down the tears. “Both of us.” Casey insisted, as the Kraang and robots got closer. “I can’t Casey.” “Please!”

Leonardo holds the fiery gaze of his student, he definitely got it from his mom. Shit. 
“When this is all over,” Leonardo said, grabbing Casey by the shoulder tightly, running to the portal “grab a slice!”

The intense red light from the suited up Kraang suddenly illuminated the space right beside them, the lazer so hot it felt like you were boiling for a few seconds. The turtle jumps with all his power through the magic gateway, still holding Casey. They fly through a tunnel of dazzling of yellow and orange. Then then suddenly they were… someplace else. 
Leonardo had clutched the teen tightly to his plastron, protecting his soft body from any harm that might come to it. They exit the portal aggressively, Leonardo is thrown shell first against a rough and cold brick wall, his arms still around the human.  
His mask had flown from its place atop his head during the mess of a trip, it skidded a little away from them as they finally exited the portal.

It was colder, not constantly humid like always. The sky was clear and lights in many neon colors illuminated the space from beyond the dark alley they had been spit into by the portal. “We… We made it?…“ he mumbles, getting his bearings. “I can’t believe we made it!” 
Casey felt like his heart was soaring. He crawls from Leonardo’s grip and stares at the unfamiliar and amazing sights before him.

He turned to his teacher with a big grin, “Sensei! We ma—Sensei! Are you okay?!” He exclaims, his stomach dropping into dread at the new wound on Leonardo’s side of his plastron. The turtle tries to answer but all that comes out is a pained groan, bringing his robot arm to clutch at his bleeding left side. 
The wound looks extremely painful and the cartilage of the plastron there is hot to the touch. The lazer… Casey realizes, his brows furrowing as he gets some bandaged from his pouch. “Here Sensei, let me help.” He offers anxiously, helping the older to a better sitting position, leaning his back properly against the alley wall. 
The teacher’s left elbow had begun bleeding through its current bandage again, but for now it would hold. He had to focus on the side injury.

Casey’s breath comes out too past and his hands are shaking as he unfolds the end of the roll, a cold green hand comes into view as it gently takes hold of Casey’s warm ones. “Take a breath. Steady yourself.” Leonardo says, his voice is steady and direct. It’s a rock Casey can lean on, a guidepost through his youth. 
The human takes a deep breath, clenching his hands and relaxes them. He can do this, he needs to do this, his Sensei depends on him as much as Casey depends on him now.

“I’m good… let me see your wound.” He says, focusing on his task. 
A small pleased smile grazes Leonardo’s lips at the teen’s new calm, he lifts his flesh arm with another groan and Casey begins wrapping the wound securely.

“We need to warn my… the turtles about the key. We can't do this ourselves with me like this. I know a shortcut to their lair.” He says a bit breathless, but strong nonetheless.  
Casey quickly locates and gathers his mask that had flown off during portal exit. Leonardo leans his weight against the wall as he shakily stands. 
Casey nods at the previous instructions and follows Leonardo to the manhole a little further down the alley. 
The student is quick to grab hold of it before the mutant gets a chance to bend down to lift at the heavy metal cover. “I’ll do it, don’t strain yourself, please…” he pleads to his teacher.

“You're a lifesaver Casey Jones.” Leonardo says proudly.

“I learned from the best.” He replies, with a grin.

——

The trek to the lair was quiet, other than the dripping of water or skittering of the occasional Rat. 

Leonardo felt like he was walking through an old memory, in a way he supposed he was. He wasn't supposed to be here, it was a long dead past on his end, yet he had to push on. He owed it to everyone to not let all that shit happen again, he would rectify his mistake even at the cost of his life.

The older stumbles again, Casey is quick to catch him. “Here Sensei, lean on me.” He offers, sliding under the hard metal arm of the other. Leonardo mutters a tired thank you to his student. They had to hurry, there was no time to take a nap, not now. 
Beside him, Casey wipes some of the blood off his own face with the back of his free hand. The older one is relieved the teen wasn't seriously hurt, he would never be able to handle losing his last family member. Being the reason another person that he loves dies.

Leonardo lets his tired eyes glide to the tunnel wall, following each label of numbers by the different sewer tunnels as they pass, he still knows them like the back of his hand. The repetition of letters and numbers was calming though, despite not actually having read much the last few years.

T85…T86… T87! There it is. Leonardo gently nudges his head in the direction of the tunnel, Casey quickly follows what he means and moves them further down into unknown territory (at least on his end.)

“We’re there soon?” He asks quietly, his voice lightly echoing down the cold metal tunnel surrounding them. The teacher looks up as they near the end of the tunnel, a soft and somber smile on his face.

“We’re already here.”

——

The time travelers stumble their way into the abandoned subway station that had become the turtle-family’s home after the Shredder fight, just the sight of it all made Leonardo’s anxiety spike.

No… he didn’t have time to dwell on it, he was there for a reason, 

“Call out to them.” He instructed Casey, not having much strength to raise his own voice. The human looked hesitant for a second, but complied. “H-hello?! Michelangelo! Donatello! R—Raphael!” He called out, the last name forgein in his mouth but familiar to his ears. 
Again, his voice bounced off the walls and it wasn't before long that four pairs of footsteps began closing in on their location. Leonardo wanted to sit, to rest, but if this needed to work he needed to appear reliable and strong, despite his injuries. 
He tried squaring his shoulders back.

A little further into the lair, a younger voice of Donatello rang out. Dry and annoyed in tone, just the distant sound itself felt like it was slowly already ripping apart the older Leo’s heart with a cheese grater. “No, I don’t know why my alarm was not triggered.” He sighed annoyed before finally appearing in front of a Leonardo and Casey. Following close were two more mutants none of the apocalypse survivors had ever expected to see again. As well as a young Leo. 
Their weapons were ready in hand, but slack grips and confusion all over their faces.

Everyone stopped in their tracks, silence and tension thick as the brothers properly laid eyes on the intruders.

Leonardo thought he could handle it. Seeing them all, but… seeing Raphael , his older brother who now wasn't much younger than when he died in Leonardo's own timeline. 
Leonardo went stiff beside Casey, making the teen look at him in question. 
Seeing Raph… it finally broke that thin hanging thread he had used to keep his composure through it all so far. 
His plan to appear calm and steady flew out the window.

The tears came fast and hard, he was unable to stop them rolling down his weathered and scaly cheeks as he pulled his shaking frame from the teen beside him. For a moment he wobbles, free of Casey’s smaller body supporting him, the student nervously calls out “Sensei!!” in a panic when his legs almost give out.  
He’s weak and his side burned but he needed to make sure the red banded turtle was really real, that he was alive and safe and that he knew Leonardo was sorry… he was so goddamn sorry.

He was tunnel-visioning on the big teen in front of him. Raph looked a mix of on edge and worried as he eyed the bloody bandages on Leonardo’s body, as well as the big prosthetic arm. 
The older Leo is huffing and trying to choke down the tears and fast breaths as his adrenaline and emotions spike, seeing the red banded turtle. 

Leonardo’s arms stretched out, both flesh and metal as he desperately gripped the steady shoulders of the snapping turtle. Raph jolts at the sudden and unwelcome contact, but can’t find it in himself to tear himself from the older. 
“I-I’m sorry, Raph.” The man choked out, his mind replaying the unfair death of his brother over and over as that old guilt filled scar in his chest was cut open all over again. “I’m sorry… I tried, I really tried…” he sobbed, feeling his legs finally giving out on him as he slid to his knees. Surprisingly, the nonplussed teen followed him down, kneeling as well.

“I… I don't understand.” Raph says, his voice wavering as he sent a confused look to his equally taken aback brothers. Behind the Old Leo, a human teenage boy stood, he looked as lost as they felt too.

Casey had never seen his Sensei like this before, so broken… It was like the immovable man he had anchored himself to was melting away, leaving a sobbing child in its place. It broke his heart in a million pieces. 
It wasn't a secret his Sensei had a lot of hurt buried in him, even regrets, but this reaction was nothing he had seen before. He knew Raphael had died a few years into the invasion, before Casey was even born. He had protected Master Leonardo, and it cost him his life. Sensei never went into more detail, he felt like he was beginning to understand why.

“I couldn’t do it,” the older Leo sobbed, “I’m sorry I wasn’t s-strong enough. You could have d-done it… protected them. I let them die, I let them a-all die…” Raph felt his stomach drop, what the hell was this?!

He firmly gripped the forearms of the older, trying to remain calm despite the storm of emotions stirring up in his chest. “L-Listen, old man…? I don’t understand. Why do you look like Leo? Who are you and why are you acting like we know each other?” He questioned, his head feeling like a mess at the amount of confusion filling it. 
The older looking Leo seemed to snap a bit out of his hysteria as he attempted a few deep breaths, reminding Raph a bit of how Leo handles his panic attacks.

Leonardo snaps his arms back to himself as if he was burned, surprising the snapping turtle. “I-I’m sorry… fuck, what am I doing?” He mumbled the last part quietly to himself, wiping hard at his eyes with his normal hand.

Beside them Mikey, Leo and Donnie are staring at the two. 
Mikey is gripping his hands together nervously at the odd scene unfolding in front of him, his eyes flitting between his brother and the… stranger? in front of him.

Donnie’s eyes are fixed on the battered sword hanging off the back of the older looking Leo’s shell. The handle, bound in the colorful masks of what could only be himself and Raph’s, no trace of Mikey’s however. The words the older had said, apologizing for deaths… damn time travel and the shit it brought with it.

Leo felt like the floor had disappeared from under him as he stared at the battered and bloody body of what could only be himself, though much older. The things he was saying, his arm, his wounds, the random human teen behind him, what the hell!? 

Finally someone other than the older Leo moved, Casey stepped up to Leonardo, setting a supporting hand on his shaking shoulder. “Master Leonardo, we need to brief them, and you need medical help!” He said worried, the older’s bandages were getting more and more blood soaked. His teacher is strong, but even he couldn’t just push through bleeding out. Leonardo was finally able to tear his still wet and red eyes from Raph’s shocked ones to turn his head to his student. 
He sighs shakily, nodding once before letting Casey help him stand up.

“ When are you from?” Donnie says from the sideline, Leonardo isn’t surprised by the question, his twin had always been so observant. He steels his gaze and looks into the young Donnie’s eyes. The other squirms a bit at the intensity, not used to seeing Leo (any Leo) ever be so serious. 
“Twenty-forty-four, everything, everyone, is dead. An alien race destroyed the world, nothing is left.” Leo grunts and winces, holding his side as it seems pain is finally catching up to him again.

“S-sensei, you need to lay down. And we need your wounds cleaned and re-bandaged!” Casey exclaims, looking around for a chair or bed. The youngest turtle steps forward, a hesitant look on his face still. 
“Come to the lounge, we have dad’s comfy chair.” Mikey offers. He attempts his best to smile at the older version of his brother. Even if he wasn’t completely the Leo he knew, it was still Leo, he had to help him. 
“Thanks Mikey…” Leo groans, still leaning on Casey.

Raph steps forward, holding out one of his big arms. “Want any help?” He asks. Leonardo bites back the tears and courtly nods. He lets the red banded ninja support his other side as they get him to the lounge.

Sitting down in Splinter’s recliner is weird yet welcome, he had missed the smell of it. The fur and candy smell it always had from him and his various snacks that had probably fallen in between the lumpy cushion and armrest over the years. He sighs, finally getting off his legs, then winces as Casey begins unwrapping the bandage around his torso.

The younger Leo quickly portals to his medical stash to get painkillers, something to clean the wound and new bandages, returning with his arms full, handing it to Casey. The human shoots the other an odd look, but thanks him nonetheless.

Leonardo let’s Casey work as he begins his tale again, the younger turtles all standing in front of him. They look nervous, it makes sense though based on the half explanation they had gotten so far. 
“The aliens, they’re called Kraang. There is a key here in New York that can open a portal to their prison dimension and let them into our world. That can not happen, under any circumstances.” He says, looking all of them in the eye intensely.  
The brothers quickly look at the young Leo, baffled that their joke-loving brother would ever end up this serious. Leo turns his face away from his brothers.

Casey uses the cleaning alcohol solution to disinfect the deep and irritated wound, apologizing quietly as Leonardo grunts in pain for a few seconds. 
The teacher grips the armrest roughly with his flesh hand before continuing. “That key will be stolen by The Foot, tonight . We nee-“ Donnie’s armband screen suddenly goes off.

“Gah! What is all this racket— oh that’s me, sorry.” Donnie taps the screen a few times. “Looks like we have a three-seventeen-da-“ “Three-seventeen-dash-three-nine-point-four. You need to go, now.” Leonardo finishes before him. 
Donnie’s jaw seems to have unclapsed from his skull as it just hangs, his eyes wide staring at Leonardo.

“You… You read my Big book of bad guy codes?” Donnie asks, gobsmacked. 
The older Leo lets himself grin for a few moments, “I’ve probably read it over thirty times. And you guys need to go, it’s the alarm for the key being stolen. I can’t join you due to my injuries, Casey will stay here too since he has no mystic powers to keep up during the chase.”

The brothers exchange a few looks between each other before nodding, moving to exit the lounge.

“And…” Leonardo hesitates, making them stop and look at him. “ Please be safe.” His voice shakes a bit, but his eyes remain as intense.

Raph nods.

“We will.”