The next morning, Michelangelo hums to himself as he puts numerous chemicals and such into a vat of mutagen inside Donatello's lab. He holds up the glowing substance within a beaker and puckers his lips, his eyes shaded by goofy-looking goggles.

"Hmm, I do believe this plutonium should react flawlessly with the sodium bicarbonates," he says in a British accent. "What do you think, Professor Ice Cream Kitty?"

Ice Cream Kitty meows and nods, also wearing goggles. If she could speak, her meow would also be in a British accent.

"Then perhaps we should add this hyperbole solution to Donnie's retro-mutagen," Michelangelo says as he lifts up a similar container of orange retro-mutagen.

Just as he says this, Donatello walks in. He rubs his eye, notices what's going on, and his face pales. "Mikey? HAVE YOU LOST YOUR SHELL?!" he screams.

"Pishposh and tut-tut, my good man!" Michelangelo clicks his tongue, still sounding British.

"I've been brewing that retro-mutagen for months! Oh, if you've ruined it, I swear I'll—" Donatello growls, his facial expressions changing dramatically with each word emphasis.

"Hold on dude, I got this!" Michelangelo says in his normal accent, preparing to pour his mixture into the retro-mutagen.

The purple-masked turtle launches forward and stops his brother, the two tangling and grunting as they start to squabble. Michelangelo keeps trying to pour his creation into the second beaker, whilst Donatello attempts to stop it by smacking him into the lab table and trying to grab the jar from his hands. He yanks Michelangelo backwards, sending the modified mutagen into the air. A single drop flies out and falls, landing in the retro-mutagen beaker with a small splash as the two brothers watch in horror.

Nothing happens for a moment, making Donatello let out a relieved sigh. Then, the solution glows bright yellow and starts bubbling, making the turtles panic.

"Oh, oh no, Mikey!" Donatello shrieks.

They both scream and back away as the solution gets more and more intense, bubbling over the edge, and a blast of light sends them flying into the wall. They gasp, holding on to each other and Ice Cream Kitty as their mask tails—or whiskers—whip around.

"It's gonna explode!" Donatello exclaims in a high-pitched voice.

The solution keeps bubbling. Donatello whimpers, Michelangelo gapes, and Ice Cream Kitty meows.

The mutagen stops as the light dies abruptly, leaving a normal looking beaker with some spilled remnants clinging to the lip. The three mutants stare in shock, arms still around each other.

"Aw well, that was weak," Michelangelo groans.

Donatello growls and tackles his brother, shouting and wrestling with him, hands and legs flying at one another without mercy.

"Now, you listen to me!"

"No! You listen to me!"

"I am gonna teach you such a lesson! I—"

A staff makes contact with Donatello's head and shell, Michelangelo's stomach, and then Master Splinter pressure points his sons into submission. He leans down so that his head is in between theirs.

"What is going on in here?" he asks, his tone more curious than stern as his sons twitch and groan underneath the pressure his fingers are exerting on them.

April peeks inside, immediately taking notice of the vial of retro-mutagen on the counter. "Since when did retro-mutagen start doing that?" she asks, referring to the sparkles now laced within the substance.

A few moments later, Donatello examines the substance under his microscope while the others gather around. The mutagenic cells calm down and return to normal at a record pace.

"Wow! Its bonding rate is phenomenal," he gasps. "Haha, I can't believe it! This will save me months of lab work!" He looks around at his family members, grinning as he grabs a dropper and sucks in a tiny bit of retro-mutagen from the solution. "Okay, let me see. One small drop and..." He drops the bit into a vial of regular mutagen and the entire thing turns orange. "I'm able to transform an entire vial of mutagen into retro-mutagen!" He laughs and spins to face Michelangelo. "Mikey, you're amazing!"

"I know," Michelangelo responds, clashing his action figures together.

"Wow, did we step into some kinda alternate dimension here?" Raphael wonders out loud, glancing at his brother.

"Question is...will it work on Karai?" Destiny inquires, flicking her tail.

Donatello shrugs, rubbing his head. "I'll have to do more work to test that, get more of your blood, that sort of thing. But...it's progress!"

She nods, her wolf ears flicking as she rubs a sore spot on the inside of her arm. Diaval sits on the couch, a pillow clutched against his chest as he lets out a ragged cough every now and again.

The purple-masked turtle looks back to Michelangelo. "Okay, what chemicals did you use to help create the rapid cellular bonding?!" he asks, his tone almost desperate with excitement.

"Uh, I think I added a bunch of stuff like uranate, anolite...uh, moronic acid, and some...uh...garlic-cappuccino pizza?" The orange-clad turtle shrugs and keeps playing with his toys.

"Nope. Same dimension," Raphael confirms.

Donatello's face falls into shock. "Are you kidding me? You do one awesome thing, and you can't even remember how you did it?!"

"Donatello, be glad that Michelangelo's tomfoolery yielded the gift that it did," Splinter scolds gently. "Focus on the goal at hand. You must find all of the transformed people of New York and change them back."

"But Sensei, we don't even know what happened to them," Leonardo points out.

"I think I know," April says softly. She looks up at her friends, her knees pulled to her chest and her pupils dilated, almost crazed. "They were taken to Dimension X by the Kraang. I can see them in my dreams, millions of mutated humans...trapped there."

"Creepy..." Destiny whispers.

"So we drop in to TCRI, break into their portal and zap ourselves to Dimension X," Raphael decides, punching his palm with his fist.

"Yo, we can do this! We can save New York!" Michelangelo squeals.

"And I've got the perfect new invention to storm Dimension X!" Donatello perks up.

----------

"A water tower."

The four turtles and Destiny stare at the giant tower, looking skeptical. Leonardo, who had just spoken, crosses his arms and arches an eye-ridge questioningly.

"That's your new invention?" Destiny asks, her words slow and calculated.

Raphael and Michelangelo burst out laughing, making Donatello frown.

"Wow, that's one giant step for turtlekind, Donnie," Raphael teases. "Nice."

"It's not exactly what it appears to be," Donatello says, deadpan.

"Get down!" Leonardo orders as a Kraang spaceship comes their way.

They duck underneath the tower as the ship floats by, scanning the area with its purple lasers. The teenager team peeks out from the shadows, the turtles' eyes glowing white with intensity. Below them, a bunch of Kraang emerge onto a street.

"They're scanning for humans," Leonardo whispers.

They watch as the Kraang move into a house. Silence remains for a few moments before they kick the door open again, dragging a man and a woman behind them. The two humans scream and struggle, but it's no use.

"Resistance to Kraang is that which is known as futile," one droid beeps.

"Let's go," Leonardo orders.

The Kraang throw the humans down on their knees in front of a larger group of aliens. The leading Kraang readies a mutagen gun and aims it at them.

"Prepare to be mutated by Kraang!" it exclaims.

"Please! No!" the man begs as his arms surround his wife tightly.

"Don't do it! No!" the woman pleads as she quivers in fear.

Before the gun can go off, a sai and numerous other ninja weapons lodge inside the alien's body. With each hit, a blast of mutagen fires and misses the humans. A bit of the blue goop goes sailing into the air right towards the defenceless humans.

Just as it's about to hit, a blue-masked blur sweeps by and pulls the couple out of the way. Leonardo catches his breath and looks up as the two victims sit up, slightly dazed.

"Are you two alright?" he starts.

"Aah! Run!" the man shrieks.

"Alien turtles!" the woman exclaims as she takes off down the street after her husband.

Leonardo frowns and points after them. "No, that's okay! It's not like we saved your lives or anything!" he shouts, the sarcasm in his voice almost as lethal as the swords strapped to his shell.

The Kraang ready their weapons as Leonardo spins around. He unleashes a single katana and crouches in the ready position, his enemies reflecting in his blade.

"Booyakasha!" Michelangelo whoops.

The three other turtles and Destiny launch above the group of Kraang and send their weapons smashing and cutting and slamming into any droid that gets near them. Short-lived chaos ensues as they take down the entire group in the span of thirty seconds. A Kraang brain squeals and tries to run away, but Raphael's foot stops it as he squishes it into the ground.

"Let's kick some Kraang!" he shouts, spinning his sai.

Destiny twists out of the paths of the whizzing bullets nearby as three more Kraang appear. Raphael flips a board up and blocks the incoming bullets, allowing Donatello to lunge forwards, kick through the wood and plunge his bō staff into an alien's gut.

"Coming at you, Raph!" he calls, sending the little Kraang brain sailing upwards.

Raphael launches and punches the creature from the air as Destiny and Leonardo spin and slice through the last few Kraang. A Kraang surveillance probe comes sailing towards the group with its multiple guns blazing. The turtles and their female companion dash away with a few yelps of surprise.

"Stupid probe!" Donatello snaps.

"Hiya!" Leonardo grunts as he chucks a garbage can lid at the giant machine.

It lets out a loud beep as the lid hits its mark, the bullets ceasing momentarily. Michelangelo flips forwards and sends his kusarigama chain flying. It wraps around the probe and pins its many arms down as he pulls it to the ground with a grunt.

More Kraang appear behind the orange-masked turtle, guns at the ready, but he shows no fear.

"Back up off me, yo!" he whoops, unraveling the chain and sending the probe smashing into the advancing adversaries. They go down with squeals and mechanical beeping.

"That all you got?!" Raphael demands as he yanks his sais from a deactivated Kraang. More bullets start flying as yet another fleet of Kraang appear. He dashes back as he avoids the lasers, screaming, "Apparently not!"

"That was a rhetorical question!" Destiny shouts as she deflects the oncoming bullets with her trusty uchigatana.

The mutants back away and regroup, standing back to shell with one another as the Kraang surround them.

"This isn't good, bros," Michelangelo says, his stance rigid.

The aliens' guns cock and whir, but then a loaf of bread hits the lead droid in the head. It stops and stoops down, picking up the baked item and staring at it with its emotionless purple eyes.

"Oh, bread!"

A grey and pinkish form tackles the droid, making wild noises as he pecks rapidly at the loaf of bread. He stops and looks up at the turtles and Destiny, his red and yellow eyes big as his beak turns up in a grin. Instantly, the turtles recognize the goofy pigeon mutant, whilst Destiny just stares in completely confusion.

"Oh, hiya fellas!" he chirps in a high-pitched voice.

He flashes a thumbs up sign as his army helmet slips a little. The Kraang start launching bullets, completely avoiding the pigeon-man. A loud roar sounds from nearby as a giant scaly creature blows by and attacks the Kraang, ripping them apart easily. Michelangelo's eyes widen as he notices the alligator mutant.

"Leatherhead!" he exclaims.

Destiny frowns a little. "That alligator you mentioned when I first met you guys? That's him?"

The turtles don't answer, still shocked by the reappearance of two of their allies.

A bunch of the remaining Kraang's eyes go blue and they turn on one another, their guns going off. They are promptly shot to bits. A chimp mutant sails into the battle scene, wearing a Kraang-like helmet, wrist cuffs, and belt.

"Doctor Rockwell?" Donatello wonders out loud.

"Who in the what now?" Destiny inquires.

The pigeon mutant soars by and snags another piece of bread in his beak as he squawks, flying through the air with his tattered wings.

"Pigeon Pete?" Raphael mumbles.

"Still don't know who these guys are!" Destiny says loudly, her ears flattened and her face distressed.

The Kraang shoot bullets at Pete, making him scream and fly unsteadily away from the danger zone. A dark shape looms out of the shadows and starts breaking Kraang apart like nothing, every single robot being torn down. When the gigantic turtle mutant comes into view, Leonardo narrows his eyes.

"You," he growls.

"Greetings, turtles! Long time no see," Slash greets, placing his mace on his spiky shoulder.

Destiny grips her curls, very close to ripping her hair out. "Who are these people?!"