Casey and Michelangelo stand side by side, peering out the slit in their cage's wall. Casey has his mask flipped down although it does little to hide how angry he is. His eyes tell all.

"I don't want to say I told you so about Mondo," he starts. "No, wait, I totally want to say I told you so!" he snaps.

"Psst, guys!"

"Mondo?" Michelangelo asks.

Mondo's face appears, upside-down, in the gap. "Sorry about all this, dudes. Fishface is bogus!" he says. He opens his mouth to reveal that he has his tongue wrapped around a key. "Totally getting you out of here."

He scuttles down to the lock and jams the key inside, twisting his tongue as much as possible. Before he gets too far, a spotlight turns on and Mondo squeaks, falling off the wall and making the spectating boys flinch.

There's the brief shrieking of microphone feedback before Fishface's voice is heard. "Oh, Jason, Jason, Jason. You were one of my most promising errand boys, but helping the enemy escape? You are dead to me. In fact, let's make that official, eh? You're going to compete in the race!"

Mondo's tail curls against him as a light switches on, showing a viewing room jam-packed with mutant baddies from all over New York.

"Right now!" Fishface continues.

Mondo plasters himself against the cage wall. "Double bogus."

"Totally," Michelangelo squeaks.

More spotlights switch on as the cage doors swing open. Casey and Michelangelo walk out into the light as Fishface swings down from the ceiling, microphone in one hand and the other securely gripping the rope holding him up.

"Ladies and gentlemutants! In tonight's race: five competitors, one survivor! No rules!" he bellows. "Whoever crosses the finish line first wins in Mr. X's X-treme Skate to the Death Death-a-thon 5000!" The words light up on the wall behind him as he says it. "Can you dig it?" Cheers and hollers sound from the audience.

"Dude, you see that audience?" Casey asks.

"It's like a who's who of evil jerkfaces," Michelangelo agrees.

They can see Tiger Claw, Emery, Rahzar, Baxter Stockman, Bebop, Rocksteady, the Purple Dragons, some Italian gang members, a giant weed mutant and spider from the turtles' previous adventures, there's even a cackling pizza slice. It's enough to unnerve them all.

"Meet tonight's racers!" Fishface calls. "First, we have Michelangelo, the dumbest of all the stupid, pathetic turtles!"

"Hey, I'm smart!" Michelangelo calls. "I'm just the party dude!"

There's laughter from the audience as Fishface continues. "Next, we have Casey Jones, vigilante and obligatory human ally."

"I am not obli—oblidary!" Casey shouts. More mocking laughter.

"Third, Jason, the gecko boy, a traitor to mutants everywhere!"

Instead of laughter, there's loud boos and roars from the crowd. Mondo makes a choked noise in his throat and backs up. Fishface swings around to face the spectators.

"Speaking of traitors, please welcome the most useless, most idiotic excuse for a warrior that the Foot Clan has ever seen!" There are a few mutters and Fishface turns around to find that Diaval is not present. He snarls. "DIAVAL CROW!"

Diaval pokes his head out from the cage, his shoulders hunched and his face paler than usual. "U-Uh...hello."

"Dude, he can't skate. He doesn't even have a board!" Michelangelo hollers up at Fishface.

"That's all taken care of," he replies. He snaps his fingers.

A few indistinguishable characters enter from behind them for just long enough to shove a small go kart towards Diaval. Diaval eyes the vehicle with wide eyes and stiff limbs, but makes no noise against it as he shuffles over and rolls it towards his companions.

"And...for the first time ever, I, Xever Montes, will personally join the race!" Fishface calls. He lands in front of the four other boys, waving at the crowd as he laughs and basks in their cheers.

"Ha! If I can't out-skate a fish, I'm retiring my blades," Casey snorts.

"Wrong, dude!" Mondo warns, his anxious gaze darting between Casey and Michelangelo. He grips Michelangelo's arms as his voice gets higher and higher with fear. "I've seen Mr. X on skates. He's way faster than us! We are hosed, man! Seriously hosed!"

"Calm down, Mondo!" Michelangelo says, knocking Mondo on the head. "We need a plan. Guys, bring it in." He gestures for Diaval to join them as they gather in a huddle.

Fishface stays completely unaware of their conversations, a grin on his fishy lips. "That's right, amigos! These robolegs can't be beat!"

Stockman flies down from the ceiling with a pistol in hand. "Time to zzztart the razzze!" he buzzes. Diaval clambers into the kart as the other skaters line up. "Ready..."

"You are going down," Fishface says to Michelangelo.

"Zzzet..." The spectators and the racers poise, ready for the blank to go off. "Go!"

Casey, Mondo, and Michelangelo skate forwards and Diaval slams his foot on the gas pedal, shooting him forward. The four of them hardly get a few feet ahead before the floor drops out from under them and they go tumbling into darkness. Sparse torches shatter the inky blackness and a stone tunnel opens before the skaters as they drop back to solid ground.

"This isn't so bad, right, guys?" Michelangelo calls as they head down the tunnel.

Diaval grunts and grips the tiny steering wheel of his kart. His long legs are hunched up almost to his chest just so that he can use his feet on the gas and brake. He looks like a giant in a clown car, but at least he's keeping up.

There's a rush of air as Fishface blows past, sending the boys spiralling in place. Fishface's robotic skates have rockets on the back of them, boosting him forward. Casey grumbles something to himself as he punches the air.

"Rocket skates? No fair!" he shouts, but Fishface has already crested the first hill and disappeared.

They keep going, zooming over the first hill in close succession with each other. Mondo's eyes widen as he notices Fishface skating up to a loose pipe and the gecko is quick to warn his companions.

"Here comes more cheating!"

Fishface flips the pipe into a different position. The sound of grinding gears fills the tunnel as electrified trash can lids drop from the ceiling. Casey whips out his hockey stick. Diaval's eyes widen, the flashing lights illuminating his tired face as his knuckles go white against the steering wheel.

"Look out!" Casey calls.

Michelangelo zips through the obstacles with all the grace of a trained ninja, dodging and ducking and leaping with precision. Mondo is slightly less so, doing more dodging and ducking than leaping. Casey smacks any lid out of his way. Diaval tucks his head close to his knees and sails underneath every single lid with little interruption.

"Ha!" Casey whoops as they pop out the other side, unscathed. "If that's the worst he's got—"

"Who said worst?" Mondo asks.

The sound of rushing water comes from up ahead alongside the creaking of stone and grit moving together. Fishface is already past the next obstacle, the heels of his skates giving the teens a pinpoint of where he is.

"Aw, no! The aquarium!" Mondo shrieks, gripping his hat as he realizes what the barrier is.

"How scary can an aquarium be?" Michelangelo asks.

Fishface turns and lets out a garbled war cry. The waters ahead of them start teeming with snapping, leaping pink koi fish just like Xever himself. The boys take one look at the infested waters and scream.

"No! Can't do it!" Diaval manages to shout over the noise. His kart starts to slow down.

Casey pulls up alongside him, eyes narrowed. "Momentum, dude! Find a ramp and floor it, you'll leap the whole thing!"

"What? H-How—"

"Go as fast as you can and just trust me!"

Casey pulls ahead. Diaval gulps, grips the steering wheel, and swiftly locates the slightest of stone jumps right before the lip of the first pool. Casey, Mondo, and Michelangelo are already halfway across and gaining ground. Diaval cranks the wheel, slams his foot down on the gas, and the kart goes shooting forward with a screech of its tires.

He squeezes his eyes shut as he nears the jump, the snapping fish getting closer and closer. He hits the ramp, sails into the air, and he feels his entire body go weightless as his organs lift into his throat and chest and the stinky water splashes against his face. There's a sharp tug on his hair and he hits the other side, barrelling after the others at a breakneck speed. He reaches back and yanks a fish from his hair, chucking it over his shoulder and back to the pool where it belongs.

He catches up to the others just as they start to swerve around giant stone boulders. He swerves and jerks his vehicle all over the tunnel, narrowly missing getting crushed on multiple occasions. Mondo leaps a boulder and sticks the landing back on his board, the gecko letting out a shout of surprise at how he managed the feat.

"Hurry! Stay ahead of the arrows!" Mondo warns.

Casey, Michelangelo, and Diaval glance over their shoulders, eyebrows raised.

"What arrows?" Michelangelo asks.

The tunnel bursts with flying arrows, earning shrieks from the unsuspecting teens. Diaval again reverts to tucking himself against his knees so that the arrows completely miss him. Casey uses his goalie glove to block the arrows. Michelangelo and Mondo go for narrow dodging.

"See you at the finish line, fools!" Fishface cackles as he rolls over another button, triggering the next obstacle.

Giant stone pillars emerge horizontally from the tunnel walls, smashing together at timed intervals. The teens round the corner, just able to see the checkered rope far down the hall.

"There's the finish line! Hurry!" Casey urges. Mondo and Michelangelo gain the lead, Casey in fourth place and Diaval in fifth. "We just have to get past this last—ugh!" The smashing pillars catch him by the strings of his equipment, holding him in place, and Casey's eyes go wide as the second set comes toward him.

"Hang on!" Diaval's low voice reaches him.

Casey's jolted away from his near death just as the pillars come together again. Diaval keeps one hand on the steering wheel, the other holding Casey on board. Casey grins widely and laughs, thumping Diaval on the back.

"Yeah! You're getting the hang of this!" he whoops.

"Guess so," Diaval replies. "Keep hanging on."

"Floor it, Wiz-Kid."

The kart jolts and speeds up. Far ahead, Michelangelo and Mondo are just gaining on Fishface, but he's still too fast and he's still got tricks up his sleeve.

"Xever's gonna win!" Mondo cries as an oil slick goes off, coating the tunnel floor in slippery black goop.

"No way!" Michelangelo shouts. They start skating up the rounded walls, crisscrossing over one anther and gaining momentum with every swoop. "Now, Mondo! Like a pro!"

They hit the oil and clasp hands. The reptilian mutants spin in tight circles, gaining speed as their tongues and faces wiggle, and Michelangelo releases Mondo's hand on the upswing. Mondo goes sailing down the tunnel, skating up the walls at a breakneck speed. He quickly gains on Fishface, zooming past him with a laugh.

"Whoa, pardon me!" he shouts.

Fishface can hardly get a word out. "Eh?"

Mondo skates up the wall, latches his padded fingers on the ceiling, and dangles his skateboard in Fishface's path. "Cowabunga!" he cries.

He clotheslines Fishface and, in the moment where they're both falling back to the ground, Michelangelo gains the upper hand and zooms past. Fishface growls and pounds the ground with his fist, activating another button.

"It's not over yet!" he warns.

"Go, Mikey, go!" Mondo cheers.

Flames bursts from the walls ahead of Michelangelo, hitting him with a wave of heat. His eyes widen and he gulps, but doesn't slow down. He screams as he vaults over the first wall of fire, the flames licking at his shell and earning a cry of pain, but he gets by. Fishface jolts upwards when he sees that the turtle survived, snarling.

"No one...beats...Xever!" he bellows.

His rocket skates turn on and he blasts off, knocking Mondo onto his face in the process. He catches up to Michelangelo and knocks his skateboard out from beneath him, but the turtle isn't about to give up. He hangs on to Fishface, both mutants struggling as they fly face first towards the finish line.

Mondo gets to his feet, shoulders slumped, but turns when he hears a shout from behind.

"Don't count out Casey Jones and Diaval yet!"

Casey smashes his hockey stick right into Mondo as Diaval's go kart goes whizzing by, sending him flying like a leopard-spotted hockey puck. Mondo zooms up to where Michelangelo and Fishface are mere hairs away from touching the finish line and shoots his long tongue out, snapping the rope and solidifying Mondo Gecko as the winner.

"Yes!" Michelangelo cheers.

Fishface hits the ground and rolls away. He pants heavily, his tail lashing as he snarls. "No! NO! You cheaters! You are hideous examples of bad sportsmanship!" he tantrums.

"We didn't cheat!" Mondo snaps. Casey and Diaval appear in the tunnel, the go kart braking with a heavy wheezing noise. Mondo glances between his three compatriots. "We looked out for each other. You told me, on the street it's every mutant for himself," he continues, standing over Fishface with steely resolve. "Well, you're wrong, dude! Friends don't let friends get kicked off of buildings!"

He turns and high fives Casey and Michelangelo. Diaval avoids the high five, giving a thumbs up instead.

"Jason!" Fishface snaps. He pulls a large switchblade from his belt and brandishes it. "You are a traitor!"

"My name is Mondo Gecko!" Mondo retorts. He hisses and lunges at Fishface. He waves his tongue, thrashes an invisible guitar, and aims a fist at him. "Cowabunga!"

He chokes as Fishface punches him right in the mouth, grasping his tongue. Mondo makes a few gagging noises before he slips out of Fishface's grip, the mutant giving him an uninterested look.

"Seriously? That is all you got?" he asks.

There's a loud rumbling from behind the back wall and Fishface turns around. A ferocious howl sounds as the ShellRaiser comes bursting into the room, skidding to a stop right before hitting the Foot Clan mutant. The battering ram deploys and smacks Fishface into the nearby tunnel a second later before Leonardo and Raphael leap out in front of the vehicle, weapons ready.

"Right, Raph. Doesn't look like they got into any trouble at all," Leonardo comments.

Destiny appears from around the back, her pink tongue lolling from the jaws of her wolf form. "Woah, that was awesome!" she says, shaking out her fur. She looks over at Casey, Michelangelo, Diaval, and Mondo Gecko and instantly reverts back to human form. "Guys!" she greets. "You're okay! And...you have a gecko friend."

"Dude, you didn't say anything about a wolf dudette!" Mondo exclaims to Michelangelo. The turtle shrugs.

"You haven't heard the last of me, turtles!" Fishface threatens as he wobbles to his feet.

He lets out an evil laugh. The smashing pillars in the tunnel go off, bashing the pink fish relentlessly as he gets knocked further and further back to where he came from. April and Donatello leave the ShellRaiser, April immediately noticing Mondo.

"Aw, and who's this lil' guy? He's so cute!" she coos, squatting down to his level.

"You ain't so bad yourself, sweetheart," Mondo says. He sticks his tongue out. "Glah."

"Eugh!" April yelps, straightening up and away from him.

"Mr. X isn't your boss anymore, Jason," Michelangelo says as he moves closer to his friend. Mondo gazes up at him. "You're free."

"I'm...free?" Mondo repeats, his unblinking eyes sparkling. They join hands and do a quick bro hug.

"Gotta admit, you're a pretty cool little gecko dude, dude," Casey says.

"Thanks. You guys are the best!" Mondo grins. He rubs the back of his neck. "So, Mikey...can I say 'booyakasha' sometimes?"

"As long as I can say 'cowabunga' once in a while," Michelangelo says. He winks at the others. "Like right now!"

"COWABUNGA!"

The others glance at one another, most expressions utterly confused as to what's going on. Destiny clears her throat and looks pointedly at Casey, Michelangelo, and Diaval.

"So..." she starts. "How did your day go?"

Diaval points to the go kart parked behind them. "Got a kart."

"Other than that?" Casey whistles. "It's a long story."