Author's notes: I grew up on the 1987 turtles, watched the 2003 cartoon a few years ago (thank you, people on YouTube), read the comics (Mirage and IDW), fell in love with the 2012 CGI cartoon and saw a few movies, and at some point during the past four or five months the bug bit me and didn't let go. This is part of the result.

So this is set during Turtles Forever, just after the 2003 turtles' lair is destroyed and 1987 Donatello beams them all into his world with his portal-onna-stick. I love both 1987 and 2003 cartoons for different reasons, and I loved Turtles Forever, but I wanted to explore the, well, culture clash between 1987 and 2003 universes. And doing justice to everyone while keeping it in Turtles Forever 'canon', which is harder than it sounds.

Also, for the sake of continuity and drama, 2003 Leo still has the gouge in his shell from where Karai stabbed him in "Exodus". He keeps it through seasons 4 and 5, so it's safe to assume it's still there despite the art change in the Fast Forward and Back to the Sewer seasons.

Thanks a lot to ChaosandMyahem for being an awesome beta no matter what I throw her way, and to Gwydion for her beta skills, patience, and 1987!verse expertise! :o)

Disclaimer: The Teenage Mutant Ninja Turtles were created by Kevin Eastman and Peter Laird, and apparently these days are owned by Nickelodeon. I own zilch, except the cover picture, which I hope you like.

Culture Shock

Eight turtles in a phone booth. This should never have worked.

But it did.

Donatello barely had time to feel a headache coming on at the frustratingly nonsensical physics of this brave new world as they all barrelled down the tunnel in a tangled mess of limbs. One minute he bumped against Raphael's armpit as Leo's foot hit him in the face, and the next he was squashed on the floor under the other three – no, he amended half a second later when the second wave of turtles hit him, the other seven.

Ouch.

"Welcome home, my turtles." The voice was foreign, yet felt familiar. "And … my turtles!?"

Donatello's jaw dropped at the same time his brothers' did.

"Master Splinter?"

The newcomer's fur was brown, not grey, and his features and his clothes were different, but there was no mistaking the warmth in his eyes behind the surprise of finding eight turtles when he expected only four. He blinked, and smiled at them. In spite of himself Don felt some of the tension and worry that had been tying his stomach in knots since the attack on their lair fade.

"Welcome to our home," Splinter said with a polite bow. The little turtles jumped off the pile with startling ease, leaving the others to pick themselves up as gracefully as they could. Which was somewhat less than they would have liked.

Predictably enough, Leo was the first to recover some sort of dignity.

"Thank you, Master Splinter." His tone was even and he returned the bow quite formally. Only someone who knew him as well as Don did could have noticed the stiffness in his shoulders and the slight crease of his brow.

Raph seemed to be making an effort to appear poker-faced, but gazed at their surroundings with an expression that suggested he was at least slightly weirded out. Mikey didn't even try to hide his shock as he stared at this world's Master Splinter.

Don could hardly blame him. And yet … For some reason, this was the first thing about this bizarre world of Eighties fashion and mutant bananas that made sense.

The awkward silence lasted about three seconds. Then the little Michelangelo's voice rose from behind Mikey and Raph.

"Dude, what's that on your arm?"

An alarm bell went off in Don's head at the puzzled worry in the turtle's voice. Instinctively he searched his brothers for injuries. He found none; they were dusty and all sported a few bruises, but nothing worse than the results of a vigorous sparring session.

The object of Michelangelo's inquiry was Leonardo – his Leonardo, not Don's. The little turtle looked startled and followed his gaze to his left arm, where a bit of blood was seeping into the blue band from a small but deep-looking cut just above his elbow.

"Oh." His eyes widened. "Ow."

He appeared more bewildered than in actual pain, but the sudden vulnerability on a face that had so far only alternated between cheerful and focused expressions stirred something unpleasant in Don's chest. "Does it hurt?"

"No, not really … not much. It's okay, guys," Leonardo said to his fellow turtles, who had paled and closed ranks around him. "Really."

There was something in his voice that made Don pause. Not really a quiver, not even a tremor, but something wasn't quite right.

"Do you mind if I take a look at that?" he asked gently, glancing at Splinter for his permission as well. If this Splinter was anything like their own sensei, he would be worried and probably unwilling to leave one of his charges in the hands of a stranger. "We have … some experience with this sort of thing."

But they were not exactly strangers, were they?

Splinter stared at Leonardo in obvious concern, but nodded. Leonardo returned his gaze steadily enough. "Grab everything you can think of," he said to his Donatello. "We'll be right back."

For some reason he threw a curious look at Leo – Don's Leo – before walking off. Don followed him into what turned out to be the bathroom.

What little Don had seen of the other turtles' lair so far had been bright, clean, and surprisingly homey. The small bathroom was no exception. It had a warm, soft sort of feeling, not unlike his memories of their first lair. Since those memories were over five years old (although sometimes it seemed longer), he knew nostalgia probably coloured them at least a little, but he couldn't help making the comparison.

The cold, leaden weight in the pit of his stomach came back without a warning. Their home was gone, and Master Splinter …

Stop, Don told himself firmly. Their father was made of tough stuff, he had seen worse, and they would get him back once they got back to their own world. In the meantime, there was something he had to do.

Speaking of …

Leonardo had retrieved supplies from a dusty first-aid kit under the old bathtub. Like pretty much everything in this universe, it was colourful, with soft round angles.

Don raised an eyebrow.

"This doesn't look like it's been used a lot recently."

"We've never needed it before," Leonardo pointed out candidly, drawing two collapsible chairs for him and Don. "Most of the time I even forget it's there at all. We fight Shredder and his Foot soldiers every other day, but the worst we get is usually bruises. Even a house falling on top of us isn't that bad."

Don almost smiled at that. A world in which you could pick yourself up after battle, no matter how bad, with only a few bruises to show for it? It sounded quite pleasant, in a surreal, Tex Avery sort of way.

"Do … things like this –" Leonardo pointed at the cut on his arm, "– happen to you a lot?"

Don carefully removed the stained blue band, handed it to Leonardo, and picked up cotton wool and the disinfectant bottle.

"It's unavoidable," he said absently as Leonardo hissed at the antiseptic burn. Don threw him an apologetic glance and dabbed his cut more gently. "Most of the time we get away unscathed, but sometimes … Sometimes it's different."

Leonardo's stare was unexpectedly intense. His expression was a mixture of hesitation and wariness that looked foreign on his face.

"How different?"

Don paused, wondering how to respond to that. Those versions of themselves appeared goofy, childish, and unable to take anything seriously – so much, in fact, that it proved too much even for Mikey. On the other hand, they had fought well against the Foot robots (old and 2.0 versions) and the looks on their faces after they had stopped cracking wise about the Utrom Shredder had spoken of resolution and drive.

And then they had thwarted a mutant banana attack.

Not for the first time, Don wished this world were sensible.

He finished cleaning off the blood and paused.

"Have you looked at my brothers and I? I mean, really looked at us."

Leonardo blinked.

"You think of yourselves as brothers?"

"You don't?"

"I've never really thought about it."

It made sense, considering their counterparts' surprised reaction to Master Splinter being addressed as 'father'. "Anyway, have you?"

Leonardo thought for a bit, then frowned a little.

"You mean the scars."

Don nodded. "I wondered if you had noticed."

"Some of them are … pretty hard to miss." He made no effort to hide his wince. "Your Leonardo … What happened to his shell?"

Don leaned forward in his chair, resting his forearms on his thighs, and gave a small sigh. He hated having to do this. These turtles' happy-go-lucky attitudes might get on his and his brothers' nerves, but they fitted their world perfectly. In a sense, a small part of himself was actually glad that this world, as silly-looking and cartoonish as it was, existed somewhere in the multiverse. If the rules truly varied from one universe to the next, none of this world's denizens might ever end up Battle Nexus Champion. But it didn't matter. It was even comforting, somehow.

This world was necessary. Even with the mutant bananas.

This Leonardo was a competent fighter, and his team seemed to follow his lead with no questions asked, but in some ways there was an innocence about him that felt important. Would that innocence survive a confrontation with the Utrom Shredder?

Should it?

What would his brothers do?

Raph would be brutally honest, reasoning that their counterparts should know exactly what they would be up against, and maybe would even enjoy scaring them a bit more than he should. Mikey might downplay the gory parts and just warn them it would be dangerous. Leo … Leo would say that dwelling on what might happen was useless and even perilous, and tell them strictly what he thought they needed to know to defeat the Shredder – no more, no less.

Don, on the other hand, had always liked to rely on clear, tangible facts, with the firm belief that they invariably trumped speculation. What you knew about your enemy that he thought you didn't was as good as a weapon.

"Our Shredder," he began slowly, "is an Utrom – an alien – in an exoskeleton that looks like a human body. He was a psychopathic war criminal whose ship crashed on Earth centuries ago. His goal has always been to return to his homeworld and take revenge on his fellow Utroms for arresting and trying to imprison him."

Leonardo obviously had no clue what this had to do with Leo's scar, but he was listening raptly. Don continued.

"The first time we faced him, he beat us. Badly. We only survived because Master Splinter toppled a water tower on him." He paused to breathe, as well as to repress a sharp pang at the thought of their sensei – hurt, captured probably, maybe even dead. They would get him back. They had to. "The second time was worse."

Leonardo's eyes widened.

"We thought he was dead, we thought we were safe, at least from him. As it turns out, we were wrong. A few months later, he had his Foot ninjas ambush Leo. They kept on coming until he was on the brink of death. Then the Shredder threw him through a window of April's apartment and attacked us. We barely escaped with our lives that night, and for a long time we thought Leo was not going to make it."

Leonardo looked like he was trying not to be sick, his fingers clenched around his bloodied elbow pad so tight his knuckles had paled, but his attention had not wavered.

"Is that how he got that scar?"

"No, but that's where a number of his scars – and ours – come from. We took time to heal, regroup, and when we faced the Shredder again, we defeated the Foot clan and Leo sliced his head clean off. Of course," Don added wryly, "we didn't know he was an alien at the time, so we thought we got rid of him for good. But he came back. Again.

"Now, a few Utroms got stranded on Earth at the same time Ch'rell – the Shredder's real name – did, and had lived as humans ever since … only they weren't murdering maniacs, just people who wanted to go home. They had been building a Transmat device to teleport themselves to their planet. The Shredder tried to take control of the device to send the Utroms somewhere they couldn't survive and then beam himself to the Utrom homeworld to murder the rest of his species. That's when we discovered what he was. We helped the Utroms get away safely, then the building exploded with the Shredder still inside." He pointed to a long, mostly faded white line on the softer skin between his plastron and his carapace. "Come to think of it, I believe it's where I got this scar."

Leonardo's face still had an ashen tinge to it, but he gave a half smile.

"How long did it take for the Shredder to come back from that?"

"You're catching on," said Don with a slightly crooked grin. "A few months. The explosion did a number on him. I think – I'm fairly certain that he would have died if his adopted daughter hadn't nursed him back to health."

"Adopted daughter?" Leonardo's eyes bugged out a little bit, and then he shrugged. "Oh, well. Our Shredder has a mother and a brother – yours having a daughter isn't that odd. Did she know he was an alien, at least?"

"I … She must have, she didn't look surprised to see his true form." The mental picture of Karai in a fancy dress carrying that little red blob as though he were a pet was so absurd it almost made him smile. Almost, though. The memories he had of that day, even though it had meant the Shredder's final demise, still had a bitter after-taste. "I don't know when or how she found out. Some things are just too weird to contemplate.

"Anyway, her name is Karai, and things have always been a little complicated between her and Leo. I have to hand it to her, though, she's a formidable ninja and she has her own twisted honour code – we even fought side-by-side on occasion." Don paused, and looked closely at Leonardo. It was obvious the little turtle was still listening closely, but there was a definite shift in his expression – like he was struggling not to smile, if a little wistfully.

He became aware of Don's scrutiny a second too late. "Sorry," he said with a sheepish smile. Was he blushing? "She's, uh … She reminds me of someone I know."

"A beautiful but deadly female ninja with questionable employers and ambiguous morals whom you tried to bring to the good side reminds you of someone you know?" Don asked pointedly. He was surprised, nonplussed and just a little bit amused when Leonardo's blush deepened.

"…Yes?"

"Oh, boy." Perhaps there was such a thing as constants in the multiverse? Don smiled, but resolved not to breathe a word to Leo about it. "Complicated" was one hell of an understatement when it came to those two.

Don shook his head and resumed his story. "Well, Karai was the Shredder's most faithful lieutenant and she obeyed him almost blindly. So I guess she fished him from the ocean when their freighter sank during that 'replace the President with a robot' thing …"

Leonardo stared at him. Don replayed his last sentence in his head and decided he couldn't really blame him.

"Don't ask," he sighed. "Anyway, since he couldn't build a Transmat, he ended up building a spaceship under his mansion to go back to the Utrom homeworld and take his revenge. Long story short, there was a big fight. Karai helped her master get to the ship, but we managed to hop on board just before take-off. Then it was just us – Master Splinter, my brothers and I – against the Shredder and Karai."

Don drew a sharp breath and willed himself not to shiver. Time had passed since, wounds had healed, most scars had faded, but some things never went away.

Sounds. Images. Smells. Tastes. The same broken thoughts going in circles in his head as the seconds ticked away to certain death.

The smell of burned hair, for example, so strong it clung to Master Splinter for days and days afterwards – although Don suspected that at least part of it had been in his own head. Steel tearing through plastron, muscle and carapace, Leo's short, breathless gasp that turned into a gargle, and the dull thud of his body hitting the ground. The raw anguish in Raph's voice as he screamed Leo's name, then air leaving his body in one short breath as the Shredder almost broke him in half. Mikey's strangled cry and the nauseating sound of bones shattering. The tang of blood in Don's mouth, the blinding pain in his right arm. The countdown as the numbers flashed and they waited for the ship to explode, with no chance of escape nor rescue.

The ghost sensations hit Don all at once, just as they did sometimes in the wee hours of the night, when insomnia metaphorically tapped him on the shoulder and said, "Remember me?". He didn't even need to close his eyes. In fact, he had to order himself not to.

"It was … it was a disaster. A nightmare. The Shredder had always been strong, but with his new exo-suit he was unstoppable. He electrocuted Master Splinter with a power line. Leo was fighting Karai, and he … Shredder came up from behind and knocked my brother right into Karai's sword. She ran him through – tore a piece of his shell loose. That's where the scar comes from."

Each word hurt, but Don dragged them out anyway. He hadn't really talked at length about the events of that day, except with April, weeks later, as they worked on the air conditioner in Casey's farm. It had been just the two of them then, and with enough gentle prodding on April's part, he had ended up telling her everything that happened on the Shredder's ship – every gruesome detail. The injuries. The crushing sense of failure. The quiet, terrified determination. Waking up in an Utrom infirmary, hurting from all over, but finding himself and his family amazingly, blessedly alive. By the end of the conversation, Don's voice had gone hoarse and he had felt drained and chilled to the bone. April had wiped her tears and wrapped him up in a warm, loving sisterly hug.

It had not really been a defeat, not with the Shredder getting sent to exile on an ice asteroid half a galaxy away, but it had not been a victory, either.

Don cleared his throat. "Raph defeated Karai, but the Shredder grabbed him and slammed him – I think he would have snapped his spine if it hadn't been for his shell. As it was, he broke half his ribs. And Mikey's legs. And my right arm. It was like getting hit with a sledgehammer. Then I blacked out."

He let out a shuddering breath and paused. If he had thought that Leonardo looked pale before, he had been wrong. The turtle had gone completely still, staring at him as though seeing what Don was seeing in his mind, every single muscle in his body tensed. His hands were still gripping the blue band so hard it had to hurt. The blood on it was starting to go brown in some places.

"I think a missile shot from Earth must have hit the ship, because when we came to, all the safety doors had come down. The Shredder and Karai were behind a bulkhead, trying to get it open. To this day, I don't know why he didn't finish us off.

"There was nothing we could do to stop him from reaching the Utrom homeworld and committing genocide at that point, so we decided to blow up the ship by overloading the power core."

"Blow up the—" Leonardo's voice sounded a little strangled. He stopped abruptly. "Oh."

Then, to Don's slight surprise, he nodded sombrely and met his eyes with an expression that was eerily reminiscent of Leo.

"I understand."

You would, Don caught himself thinking. Maybe there were constants in the multiverse, after all – and if there were, then Leonardo having at least an intuitive understanding of the concept of self-sacrifice was right at the top of the list.

Instinctively, Don resolved to keep an eye on the little guy. There was no way he would let things come to that again.

"So, what happened next? I mean, you guys obviously didn't die, so the ship—"

"Did explode. But the Utroms had received a distress call one of our friends had sent. They arrived just as the explosion started. They put the ship in stasis for a few seconds, took us in the infirmary and locked up the Shredder, Karai and the scientist who piloted the ship. We witnessed their trial. Karai and Dr. Chaplin were sent back to Earth and handed to the authorities, and the Shredder was sentenced to exile on an asteroid, in a galaxy far, far away." Leonardo's eyes lit up slightly at the Star Wars reference. Don gave a small smile, then sobered up.

"And now he's back. Look, I'm not telling you all of this to scare you. It's just … I want you to fully understand just how dangerous our Shredder is. I don't mean to brag, but we are ninjas, and Master Splinter trained us well. We face threats – serious threats – all the time, and generally, we come out on top. But with the Shredder? He's beaten us more than we beat him. He's violent, he's ruthless, and he never lets things like honour or compassion for fellow living beings get in the way."

Leonardo seemed to blush again, but this time, it had plainly nothing to do with feeling self-conscious.

"You think I'm scared?" he asked hotly, eyes shining.

"I think you should be. Your Shredder sounds … well, quirky in comparison."

Just like that, the anger was gone. "He is. Sometimes he's an idiot. And sometimes, he's a dangerous opponent … Just not the kind that runs people through or breaks legs. Because we don't let him," he added with a seriousness that was, again, eerily familiar.

Then he glanced at the nick on his arm. It had started to bleed again slightly. Don picked up disinfectant and another piece of cotton wool.

"Our Shredder never got away with horrors like yours did. I mean, he did almost kill April once, but we …" Leonardo trailed off, and continued, his tone more uncertain, "It's like there's rules here that even Shredder and Krang obey. Us, too. What you described, what you and your brothers went through with your Shredder? That just would not happen here."

Don kept silent, sensing more to come. All of the other universes he and his brothers had seen so far, no matter how otherworldly, frightening, or downright bizarre they had been, had functioned with the same basic sets of rules, at least as far as physical violence was concerned.

If taking hits had little to no consequence in this universe, he could hardly blame the turtles for having trouble taking things seriously.

"Look," Leonardo said quietly, "I'm not afraid of your Shredder."

Don raised an eye ridge.

"No, really. I'll be on my guard and ready for anything he can throw at us. I'm the leader, it's my job. It's just …"

Don put a band-aid over the cut, ran his thumb gingerly along the fabric to make it stick, and leaned back.

"What are you afraid of, then?"

Leonardo looked down at the elbow pad in his hand, his eyes glued to the bloodstain, a dull rusty colour against the bright blue.

"How …" His eyes met Don's again, and Don was taken aback at the unguarded distress he could see there, as plain as day. "How does he do it? Your Leonardo, I mean, how – how can he just lead you into battle, knowing that can happen? Knowing that sometimes you're all just one decision away from injury and death? That it takes so little to get hurt? That it's so easy to lose someone you care about?"

An image of the last time they had seen their father, already hurt with rubble falling all around him, flashed in Don's mind. This time he didn't even try to hide the shudder that coursed through him.

"I don't know," he said gently. "I'm not Leonardo. How do you do it?"

Leonardo took a deep breath, released it slowly, and most of the anguish faded from his eyes.

"I focus on being the best I can be. The best ninja, the best leader … I always go in first, and go out last. I try to look out for my friends. When they need me, I'm there, no matter what."

No matter what. That, too, sounded familiar. In spite of the aching worry over Master Splinter, and, admittedly, how rattled he had been by the news of Ch'rell's return, Don gave a smile that was genuine and warm.

"I'm not sure my Leo would have anything to add to that."

Leonardo's answering smile was still a little strained.

"When I said I wasn't afraid of the Shredder, I meant it. I'm not stupid, I know he's dangerous, I won't try to attack him by myself or anything – but I'll face whatever comes our way. But …" He trailed off again, his gaze drawn to the half-open door. Bits of lively conversations and the odd burst of laughter drifted in from the lair. "If I can get hurt, it means they can, too. And if anything happens to them … I don't know how …"

He looked completely lost for one second, eyes dark with worry. Then he blinked, smiled, and the sun rose again.

"You know what, though? They're all great ninjas. They've never failed before, and I never failed them, either. We'll be fine. Besides," he added with a short laugh, "we know how the Technodrome works, and it's by our rules, not your Shredder's. We took that old tin can down before, we'll just have to do it again."

"Your tech, your rules, huh?" Don still wasn't a hundred percent sure this would prove true. His counterpart's approach to science felt a little too much like something out of one of Mikey's Sunday morning cartoons for him to trust it. Fixing machines with 'positive thinking' and hitting things with a wrench might work on TV, but what kind of scientist relied on that in the real world?

Then again, the little Donatello's portal-device-slash-flashlight should never have worked on that logic, either. Just because Don wasn't sure was how the 'other him' made things work didn't mean the little guy didn't know what he was talking about. And these turtles' dimension was their real world – for a given value of 'real'.

It would have to do.

Don dumped the used cotton wool into the trash can while Leonardo put the first-aid kit back under the bathtub.

"I guess it does work like that. You looked really surprised that Donatello's portal device actually worked."

"To be honest, I was," said Don dryly. "But you know what they say about looking a gift horse in the mouth. If something works, no matter how outlandish or impossible, then we can use it. I'd just like to know how it works."

These past few years, Don had met aliens and superheroes, travelled through time and other dimensions, battled mystical monsters and demons, and, on a memorable occasion, turned into a dragon. His personal definition of 'impossible' had evolved in leaps and bounds until it meant 'we don't understand how it works yet'. He had embraced Clarke's Second Law – The only way of discovering the limits of the possible is to venture a little way past them into the impossible – and made it one of his personal goals.

And still the universe – or multiverse, as it were – constantly found new ways to make him marvel at the seemingly impossible. Frustrating though it felt at times.

Leonardo grinned.

"You can ask him, but to be honest, I was surprised, too," he said. "His inventions can be little … hit and miss sometimes." He paused, and looked back at Don. "You coming? Smells like Master Splinter made us some rice. It's not pizza, but it's the best rice in the world – in this dimension, I mean. Besides, your Michelangelo is due for another noogie." The grin was back, and if the mischievous gleam in his eyes was any indication, Mikey would never see that one coming.

Maybe Leonardo's optimism was out of place, and maybe, despite everything Don had told him, he still didn't take the Shredder seriously enough. But the little guy definitely understood what being a leader meant. Don's words might have shaken him, but not as much as the thought of his friends getting hurt on his watch; he would do anything to prevent it, that much Don knew with absolute certainty. No matter how soft and round the turtle looked, or how silly he acted, this was still Leonardo in every aspect that counted.

The worry and fear for his father was still very much there, a cold, heavy weight that Don knew would not go away until they got him back in one piece, and this dimension still felt thoroughly alien and a little unsettling. But it wasn't bad, exactly – as parallel dimensions went, it was probably even the nicest Don had ever set foot in. It was colourful, cosy, even homey, mutant bananas notwithstanding. Perhaps he could afford to relax a little.

Best rice in the world and watching Mikey get surprise-noogied? Sounds tempting.

Don smiled.

"Lead the way, Leonardo."

Leonardo laughed, and led the way.

THE END

Much as I love Turtles Forever, and goodness knows I do, there are a couple of things, mostly about the 1987 turtles, that didn't sit well with me. Like the 1987 turtles running to 2003 Raphael whimpering because they're scared? Um, nope. And 1987 Leonardo was noticeably more disciplined and focused than the others, not to mention brave to the point of recklessness (seriously) which I wish the TF writers had acknowledged. It was a fun movie, though :o)

The "beautiful but deadly female ninja with questionable employers and ambiguous morals whom [Leonardo] tried to bring to the good side" is Lotus Blossom, a female ninja Shredder hires to take out the turtles. She defeats him and replaces him for the better part of the episode. Leonardo ends up falling pretty hard for her, and it's downright adorable. Come to think of it, I think she was the main inspiration for Karai, since Lotus Blossom's first appearance was in 1989, and Karai debuted in the City At War arc in the Mirage comics in 1992. That's one of the things I love most about the TMNT franchise – everything is related somehow :o]

You know, writing this made me want to wrap the 2003 turtles into a huge collective hug. Wow. The writers really were merciless, weren't they?

Hope you liked it!