Splinter could feel the wind whip past him as he fell, the cries of his children disappearing into the wind. He dodged a punch Shredder threw at him before punching him in the face.

Shredder managed to maneuver them so he could slam Splinter into a rock column, keeping him scraping against it as they fell. "You fall to your doom, rat!"

"Not doom, if my children survive," Splinter retorted, biting into Shredder's shoulder, which made him let go. Splinter maneuvered them as Shredder grabbed the bottom of his robe, getting him to slam into a metal beam.

Splinter watched as Shredder grew smaller, smacking into a few beams before finally slamming into the bottom of the abyss.

https://youtu.be/0m-PZ2Toupc

Teenage Mutant Ninja Brothers

Teenage Mutant Ninja Brothers

Teenage Mutant Ninja Brothers

Heroes in the shadows

Ninja Power!

Here we go!

It's the lean, mean, ninja team

On the scene, cool teens doin' ninja things

So extreme, out the sewer, like laser beams

Get rocked with the Shell-shocked Pizza Kings

Can't stop these radical dudes

The secret of the ooze made the chosen few

Emerge from the shadows, to make their moves

The good guys win and the bad guys lose

Leonardo's the leader in blue

Does anything it takes to get his ninjas through

Donatello is a fellow, has a way with machines

Raphael has the most attitude on the team

Michelangelo, he's one of a kind, And you know just where to find him when it's party time!

Y/N, he's a roaring cat, and he'll protect what, he loves, and that's a fact!

Master Splinter taught them every single skill they need

To be one lean, mean, green, incredible team!

Teenage Mutant Ninja Brothers

Teenage Mutant Ninja Brothers

Teenage Mutant Ninja Brothers

Heroes in the shadows

Ninja Power!

Mikey threw a smoke bomb into Rocksteady's face, distracting him long enough for Leo and Raph to slam the doors closed once again. They ducked as Rocksteady started shooting through the openings in the doors.

"He... He has to be alive, right?" Leo asked.

April shook her head. "I-I don't sense him at all. Maybe--maybe he's unconscious."

"That drop is at least 1,000 feet down," Donnie reminded them. "Even he couldn't survive a fall like that."

"So wh... what do we do?" Y/N asked.

"We take them all down," Karai answered as she got up, the gunfire ceasing. "For Splinter!"

(The doors burst open, knocking back Leo, Raph, and Mikey, since they'd been holding them closed. Rocksteady had smashed through the doors, Bebop riding on his shoulders.)

"Ah-has!" the rhino said, knocking Bebop off his shoulders. "You should have runs when you had the chance! Now I will be doing all the squishings!"

"No way, dog, we talked about this," Bebop started to argue after getting back to his feet. "I want to blast 'em!"

"Nyet, comrade Bebop." They all looked at each other, Leo nodding at Mikey before Raph moved silently into the shadows and Y/N secretly moving onto the ceiling. "I like the squishings. Is fun!"

Mikey crossed his arms. "Yeah, but guys, if you squish us, you won't get the secret information."

Bebop and Rocksteady shared a glance. "What you mean, secret information?" the rhino questioned.

"There's some things you don't know about us," Mikey responded. "We have...salmonella!"

"What?" Bebop yelled. "That's nasty!"

"You mutants are being nasty gross," Rocksteady added.

Y/N took his chance as he jumped at Bebop and landed on his back while Raph dropped onto Rocksteady. "Off me, salmonella sucker!" Bebop snapped, letting himself drop to get him off his head.

"Watch the skull!" Rocksteady said, charging forward with Raph hanging off his horn. Everyone else dove out of the way to avoid him.

"Cowabunga!" Mikey shouted as they ran after the rhino.

(Y/N flipped back onto his feet and kicked Bebop back. He continued to press forward, forcing him back as he punched him. He raised his fist, only for a rope to wrap around his wrist before he could land another hit. Looking back, he saw more of the Elites at the doorway.)

"Seriously?" he growled. "Again with these guys?" He used his claws to cut the rope before blocking the robot's blade with his. "I'm getting real sick of you." he said as he quickly cut the bots head off before running to join the others.

(He reached the end of the tunnel with the room where Karai had been held captive. He ducked as another Elite attacked, blocking the blade with his claws. Leo joined him, blocking another Elite's blade with his katana and throwing it toward where the others were occupied with Rocksteady, the rhino cutting into the robot as Riki dodged his sickle.)

(Leo sliced at the other robot, gaining its attention and drawing it away from Y/N. With the Elite occupied, he gave himself a brief respite. The claw wounds Tigerclaw had left in his back burned.)

Sighing, he looked back down the tunnel as his brother cut down the other robot. "Oh, you've got to be kidding me..." he took off running as the others noticed the Elites as well, passing Leo as they fled.

"Hurry, Leo!" Riki shouted. "Move!"

"Where are you going?" he demanded, only to turn and see the robots. "Oh, snap." He took off after them, following them up a ladder.

(They came out in one of the subway tunnels, and took off running down the tracks. A train approached and they hitched a ride on the caboose as the Elites came through the door, only to be smashed to pieces by the train.)

-x-

"Everyone can relax," Casey said, breaking the silence of the lair as he walked in. "Casey Jones is here." He tossed down his sports bag. 

Chloe soon followed with her backpack armor, "As is Chloe."

 "So, what's the deal? Why'd we get, like, 127 emergency texts?"

"The pizza delivery guy disappear?" Chloe asked.

"No," Riki said. "Splinter disappeared."

"He...he fell down that huge chasm in the Undercity," Y/N added, ears flat with Shen rubbing his head.

"Whoa. That's deep, yo," Casey said.

April clutched her crystal. "I've definitely lost my mental connection with Splinter." She loosened her grip. "But that doesn't mean he's gone. We can't give up hope."

"That's right," Mikey said, getting up. "Splinter is still alive. He--he has to be. Right, guys?" He looked around at them. "Right?"

"He is," Shen said. "I don't need any psychic powers to know that. I can feel it."

"We're going back," Leo stated. "We'll search every inch of that hole if we have to. We'll find Master Splinter. And we'll stop anything that gets in our way."

(They geared up, Donnie, Mikey, and Ethan equipping the climbing harnesses to safely descend into the Undercity's chasm.)

"Wait, dudes," Mikey started. "How come the B-Team has to do this mission?"

"Uh... I'm going with you," Chloe reminded him.

"Because we're gonna guard you from the Super Shredder," Y/N responded. "Unless you'd like to switch jobs?"

Mikey blinked. "Spelunking it is!"

"So, if Shredder is still alive, and his goons show up..." April said.

"We'll be ready," Raph said, holding out his hand. "For Sensei."

"For Sensei/Father!" they all echoed, putting their hands in.

Before they left the brothers and Karai turned to Shen as she knew she had to stay here.

"We promise, we'll  bring him back."

Shen shook her head, "Just promise you'll all come back."

Karai nodded, "We will mother."

(Shen hugged all of her children while kissing their heads before they headed off.)

-x-

(Splinter thrust his hand into the air, groaning as he attempted to sit up. He tried to move, only to yell as pain shot through his leg.)

"My leg!"

(He found a strip of white cloth beside him, taking it and managing to create a make-shift splint for his broken leg. He held onto the ends of the cloth as it was tied around the splint, steeling himself before pulling it tight, correcting the bone and making him yell in pain before falling back against the floor, wanting nothing more than to rest.)

"Wake up, Splinter." A voice prompted him to open his eyes. "You must not slip back into sleep," the voice coaxed as rats started climbing over him. "Rats must be alert at all times. I can help you, old friend."

Splinter forced himself to sit up, the rats scurrying away. "Who are you? Show yourself!"

"You sent me here. And now, you join me in the darkness." Two glowing red eyes appeared in the shadows. "Two similar, misbegotten creatures." Splinter watched the rats run past a figure that slowly began to form before him. "Hamato Yoshi, Splinter." One of the rats ran up the figure, perching on their shoulder. "And I, your lord. Your master." The figure stepped into the light, the owner of the voice none other than Dr. Falco, the Rat King. "Your Rat King!"

"You?" Splinter questioned. "But I sent you plunging into darkness. How could you have survived?"

"You survived, did you not?" Rat King countered.

"Then why are you still here? Why did you not escape?"

"There is no escape. We are both trapped like rats. But here, in the darkness, you belong to me."

"Never!" Splinter started pulling himself across the ground to get away as Rat King began to walk toward him.

Rat King simply laughed. "You only weaken yourself trying to fight me. You can never leave this place. Look at you. How can you climb with such a broken and feverish body?" He stepped on Splinter's broken leg, making the rat scream as he laughed.

-x-

"I'll stay here on lookout," Leo stated, all of them just outside the tunnel leading to the Undercity. "The rest of you, hurry up. Master Splinter needs you."

Y/N walked up to Leo with April, Karai, Riki, and Timothy. "We'll stay with you, Leo," April said.

"You need us," Karai stated. "If Shredder survived, you can't take him alone."

Leo rolled his eyes. "Well, thanks for the vote of confidence."

"Nah, we just don't want you to have all the fun," Y/N teased.

-x-

"So where did Splinter jump?" Casey asked as they entered the Undercity. "This way?"

Donnie walked to the cliff's edge, activating his harness to lock one of the cables into a broken wall. Mikey, of course, was quite excited about the spelunking adventure. "Sweet! Grapple harness time!"

"We have to take it slow, Mikey," Donnie scolded. "The walls are crumbling, so be careful. You got me? Be. Care. Ful."

"I always am, D," Mikey responded with a wink. "Booyakasha!" He dashed to the cliff and jumped, activating his harness as he fell so it locked onto the broken bridge at the cliff's edge. "Whoo-hoo!"

"Mikey!" Donnie shouted.

"Whoa, dude!" Mikey called up. "This cave goes on for, like, ever!"

Ethan sighed as he watched them go. "Take it slow, Uncle!"

"Relax, Ethan," Chloe said, activating her boosters and diving down after them. "You know I'll catch them if they fall."

"Master Splinter's down there," Donnie said as he started walking down the side of the wall. "Somewhere."

-x-

Splinter groaned, hand clutching his head. "My head." His hand slid to the ground as he laid back. "Must have fever."

"You are weak," Rat King said. "You need water. And food. Your body craves sustenance. Where could it be?"

Splinter snatched a rat that had crawled into his hand, lifting it up as he stared at it. It was true, he needed food and water, and the rat in his current state was very tempting.

He closed his eyes, breathing out. "No. I will not." He dropped the hand, releasing the rat.

"So noble," Rat King mocked as the rat ran to him. "You think that makes you more than a beast? Spend enough time with me here, and you will see you are nothing but an animal." He grabbed the rat as it ran into his palm. "An animal who must do whatever he can to survive." He shoved the rat into his mouth.

-x-

"I hope they're okay," Raph said, looking over the edge of the cliff. "It's awfully quiet down there."

"They'll find him," Ethan said.  "All we can do is wait."

"And it's awfully boring!" Casey groaned, taking shots with hockey pucks to pass the time. "I wish something crazy would happen."

(As if on cue, one of Casey's pucks bounced off some broken rocks and hit something -- or rather someone -- that had been invisible, making them visible for only a moment.)

"Ow!"

Casey gasped. "Whoa! Guys, someone's out there."

(Ethan pulled out his his kunai. Casey shot another puck, landing a direct hit on the invisible person.)

"Ah!" The wall dropped, Bebop rubbing his snout as he and Rocksteady appeared in front of them. "You jerks, you hit me in my piggy snout!"

"Bebop and Rocksteady?" Ethan questioned.

"Now, you will bring us furry rat man ninja, or we will break you like dancer!" Rocksteady snapped.

Bebop facepalmed. "No, no, breakdancing ain't got nothing to do with--aw, forget it. Take 'em down, G!"

"Look out!" Ethan yelled as Rocksteady roared, everyone quickly dodging out of the way of his hammer. Bebop jumped off Rocksteady, throwing a laser toward them.

-x-

"Master Splinter?" Mikey called, the four of them hanging in the air while Donnie attempted to get a reading of the layout below. "Hello?"

"Quiet, Mikey!" Donnie whispered harshly. "If Super Shredder survived that fall..."

"Sorry, D, but how else are we gonna find him?" Mikey asked.

"Uh, by actually looking for him?" Chloe responded.

"There are tons of caves down here," Donnie said, lowering his scanner to look at the blackness below. "He could be anywhere."

"Then we better get moving," Chloe said, diving lower into the chasm.

-x-

(Y/N kept a tight grip on his claws  his ears swiveling at every little sound coming down the tunnels toward them. His tail twitched, ready and expecting a fight.)

"They're coming," April said, having been using her powers to track movements in the tunnels. "They'll be here any minute."

"There's no way we'll be able to keep them from the Undercity," Y/N pointed out.

"We bait them to the surface," Leo said.

"No, we take them down on the surface," Karai argued. "We finish them both."

"I'm down for that," Y/N agreed.

April gasped at a growl from a nearby tunnel. "Here they come!"

Shredder, Lobo, and Tigerclaw ran into the room, the tiger spotting them first. "Master Shredder. Karai!"

"Time to move!" Leo called, leading them through the tunnels.

"I want the Turtle," Shredder growled behind them. "You can destroy the rest. Save me Karai."

(Tigerclaw started shooting at them and they bolted up a ladder to make their escape to the surface.)

-x-

(Raph clung to Rocksteady, the rhino ramming into the broken walls to try and knock him off as Ethan ran after them, flinging fire toward the rhino. Casey was on his skates, swiftly moving through the lasers Bebop shot at him.)

"I've got your punk butts now!" the warthog taunted, shooting more lasers. "Shamone, shamone, shamone, shamone!"

(Ethan ran at Bebop to try and tackle him, only for the warthog to vanish before he could catch him. He reappeared on a broken wall, shooting more lasers at him.)

-x-

Splinter groaned, looking up from where he lay at Rat King, who still insisted on tormenting him. "Once upon a time, you were a man. And then you became a beast. Now, you are nothing. A void. A shadow. Embrace the darkness Hamato Yoshi."

"To embrace it is to become a monster such as you," Splinter retorted. "Leave me."

"If you will not join me, then you will be devoured!" Rat king started laughing, Splinter watching as rats suddenly started pouring from the darkness toward the man, climbing onto him until he was covered.

They turned into a hideous monster made completely of rats, the sight making Splinter gasp. "No."

-x-

(Leo watched April flip onto the rooftop he, Karai, Y/N, Riki, and Timothy were currently on, trying to get Tigerclaw, Lobo, and Shredder off their tail.)

"Did we lose 'em?" Karai asked.

"You know, I'm gonna go out on a limb here and say--"

"Look out!" April warned, interrupting Timothy.

"I was gonna say 'no', but that works, too!"

(Tigerclaw jumped onto the roof, throwing Leo off of it. He slammed into the wall of the next building before falling into a pile of garbage in the alley. He groaned, trying to push himself up. His ears pricked at heavy footsteps drawing closer and he turned his head to see Shredder stomping toward him.)

"This is gonna hurt."

(Shredder grabbed him and threw him out of the alley, slamming him into a car. The people who had been walking in the street screamed and fled as Shredder walked out of the alley, grabbing Leo and lifting him into the air.)

"Goodbye, Turtle."

(He struggled against him, screaming as he tightened his grip and started to crush him.)

-x-

Rat King laughed from within the monster as Splinter tried to crawl away, the rat-monster roaring. "Splinter, it would be easier to accept my dominion." Rat King burst from the rat-monster's stomach, grabbing Splinter. "Become one with me, Hamato Yoshi. It will only cost you your soul."

(Splinter gave into his animal instinct, growling and smacking Rat King away, sending the man falling to the floor with the rats. Splinter got on all fours, roaring at the rat-monster reformed, Rat King on top of it.)

"Yes!" Rat King shouted. "This is what you are! A monster! A freak! An animal!" He laughed as Splinter roared.

-x-

"Shredder!" April shouted, jumping down onto the hood of a car with Leo.

Karai jumped down onto the street, Riki and Timothy flanking her. "Let him go, freak!" Karai snapped, tanto aimed at Shredder.

Shredder tossed Leo aside and he slammed against the pavement. Leo ran over to her. "Are you okay?"

"I'm good," he groaned. "Just...give me a minute. Go help them."

"Do not disrespect me, daughter!" Shredder snarled, stalking toward Karai, Riki, and Timothy. A cartsuddenly slammed into his back. "What?" He turned around, April using her psychic abilities to control the objects around her.

(Shredder created a shockwave with his hands, shooting April back as she slid across the pavement. Timothy jumped off a car before he could reach the red-head, his axe colliding with one of the metal spikes in his shoulder.)

He jumped off as he turned to face him. "I just need to find a soft spot, monster!" He jumped out of the way of his punch.

(Y/N and Lobo were going at it constantly with blades flying and sparks flying.)

"Sorry kitty, I'm just too fast." Lobo mocked.

Y/N smirked, "You sure about that?"

(Y/N suddenly jumped off the edge of the building which confused Lobo, who looked down and saw nothing until Y/N suddenly jumped up from the other side of the building.)

(Rain is Y/N and Kotal Khan is Lobo)

(The pain in Y/N's back increased as he tried to bite the pain back and go help his family.)

-x-

Raph jumped back, dodging Rocksteady's fist. "That's it, turtle scum," the rhino snarled. "Now you get the horn!" He charged, Raph jumping onto a broken wall before jumping off, dodging and making Rocksteady get stuck in the wall.

Ethan jumped down onto the ledge of the platform, whistling sharply. "Hey, rock head!" he called as the rhino pulled himself from the wall. "This way!" He held his arms out at his sides, smirking cockily. "Look at me, I'm waiting for you!"

Rocksteady fell for his taunts, rushing him. "Waiting for my horn up your--" He cut off as Ethan suddenly dropped down off the ledge, sending him tumbling over onto another platform, his hammer falling on top of him.

Ethan snickered, using his kunai to lift himself back onto solid ground. He got up just in time to see Casey knock out Bebop, the warthog falling onto the ground. "Aw, yeah!" the vigilante cheered. "Casey Jones wins in overtime!"

-x-

Splinter hissed at the rats surrounding him, the rat backing up onto a fallen metal beam overlooking an incline.

"You cannot rid yourself of me," the rat-monster taunted, making its way to Splinter and forcing him farther up the beam. "I will be with you always. In the darkest parts of your mind. I am your teacher." It grabbed Splinter's neck, pinning him down. "I am your master!"

Splinter screamed as Rat King laughed, the sounds echoing around him. His vision blurred together into a new place, and he could hear Donnie's voice. "It is a cake!"

"What's the, uh, frosting made of?" Leo asked, Splinter's vision becoming clearer, the rat finding himself in the lair on the day the turtles and Y/N  first went out onto the surface.

"You don't wanna know," Mikey responded. "Happy Mutation Day!"

"Happy Mutation Day!" his brothers echoed.

Splinter blinked, looking between his sons and daughter, confused. "Hmm?"

"Tell us the story, Master Splinter," Mikey requested, his voice echoing.

Splinter's focus wasn't on him, however. It was on the figure behind him and his siblings. The figure turned to Splinter, making him gasp. "Shen!"

(Bringing himself back to reality, he kicked the rat-monster's legs, getting it to let go before punching through its stomach. The monster collapsed into a pile of rats, allowing Splinter to rest for a moment. Only, he slid off the edge of the beam and rolled down the incline. He yelled and scrambled back when he came face-to-face with a skeleton.)

It took him a few moments, but Splinter soon realized just whose corpse he was staring at. The corpse of Falco himself. "What?" He looked up at where he'd fallen from. "It was all a hallucination. My fever. Nothing more." He glared at the skeleton. "Perhaps a teacher, but never my master."

-x-

(April threw her tessen at Shredder, the fan hitting him before Leo jumped onto his back and slammed his katana into his neck. He flipped off him when Shredder tried to grab him, only for the large mutant to smack him into the pavement.)

(April gasped when Shredder kicked her back, the red-head using her power to throw him back before he could strike her again. A semi-truck suddenly slammed into Shredder before crashing into the side of a building.)

Shredder cut through the tankard the truck had been pulling, forcing his way out. "Now I will crush the life out of all of you." He picked up the truck and flung it at them.

(The truck stopped right before it could hit them, April using her psychic abilities to hold the truck in place. She was struggling with the task, dropping to her knees as her nose started bleeding, but she refused to give up. Her eyes started glowing blue and she threw the truck back at Shredder.)

He threw it aside. Leo was crawling on his hands and knees to try and grab his sword out of the street. Shredder reached him before he could, punching him and throwing him into the pavement. He lifted his hand to take the final blow, pausing when Karai shouted, "Stop!"

She stood up. "Don't do this! You can do something good for once, Saki! Something without malice. Without the need for revenge."

"Karai. I..." Shredder moved toward the kunoichi. "I never meant to hurt you." Karai sent a subtle glance at Leo as Y/N helped him away from the fight with him still having pain in his back. "Please. Call me father. Not Saki."

"You were never my father!" Karai shouted, slamming her fist into Shredder's exposed heart.

Shredder yelled in pain, green liquid spewing from his mouth. His arm started to contort and shrivel. "No!" He started to flee. "Not now. Not now!"

Karai grabbed her blade and ran to attack, only to be cut off by Tigerclaw shooting a wall of ice in front of her. "No!"

Tigerclaw drove up in a van. "Come, Master! Hurry!"

"We can't let them escape!" Karai called.

"Karai, Y/N's in to shape to fight," Leo argued. "We need to get him back to lair."

Karai looked back as the truck drove off, Tigerclaw and Shredder escaping. "You're right." She sheathed her blade. "Next time." She ran back to them, helping Leo get Y/N back onto his feet.

-x-

"Master Splinter!" Mikey called again.

(Chloe peered around the darkness. Normally she could see in the dark with her night vision, but she still needed a bit of light to do so, and it was so far down from the top that the only light they had were the weak beams from their flashlights.)

"My..." The weak voice made them gasp. "My children!"

"Splinter!" Chloe called as they cast the light of their flashlights on him.

"Thank you, great pizza maker in the sky!" Mikey said as they reached the ground and retracted their harnesses, running over and hugging Splinter.

Splinter held them close, not wanting to let them go. "I have never happier to see such smiling faces."

[With Splinter saved, Super Shredder still demands the mutagen which terrifies Stockman-Fly.]

Shredder: Stockman! I need a stronger dose!

Tiger Claw: [Protested.] No. I will not allow this! [Puts his hand on Super Shredder's Shoulder.] It will destroy you!

[Super Shredder punches Tiger Claw sending him flying into the couch.]

Super Shredder: [groaning] Do it. [Slams Stockman-Fly onto the control panels.] Do it now!

[Stockman-Fly agrees then presses a button. The mutagen takes effect as it reverts Super Shredder's left arm to normal. Tiger Claw can only watch behind the knocked out couch with shock and fear as Super Shredder chuckles and lets out an enraged scream as the mutagen strengthens him once more...]

Hope you enjoyed the chapter!!!