Archive of Our Own ^beta

Chapter Text

“Mikey!”

Letting his chains singe through a couple of Kraang hounds, Mikey turned to look at his eldest brother. Raph was tearing through his own crowd of hounds, flinging the zombie-like creatures over his head and out of his way. When Mikey caught his eye, he pointed down a hallway, away from where Leo was protecting his portal.

“Find Casey!” He bellowed.

Mikey felt his stomach drop at the franticness on his brother’s face.

The Kraang attack had come suddenly, all due to a mix-up with this region’s Resistance outpost and a lack of updates to their systems. They had been lucky that Donnie’s personal scanners and satellites had picked up the approaching pack, otherwise more civilians would have been caught in the battle.

But Casey hadn’t been with the rest of the kids that had already escaped. A few days ago, he had caught a minor cold and had been recovering in his parents’ room. Away from the evacuations.

Shoving aside the panic at the thought of Casey getting hurt, Mikey nodded.

Pulling his mystic power around him, he vanished in a burst of light, destroying a few of the hounds that got too close.

He appeared in a hallway, close to the sleeping quarters. The familiar weight of his nunchucks settled into his hands as he summoned them, before hurrying to the first door.

“Casey?” He called, keeping an eye out for hounds as he looked around the empty room.

The next room, Donnie’s lab, was stripped clean. No sign of Casey.

He leaned into the room that he shared with Leo, Donnie, and April, a forced smile on his face.

“Now is not the time for hide-and-seek, Case.” No response.

Raph and Cassandra’s room. Mikey peeked in, hopeful since it was the last place he had seen his nephew. Dread pooled in his stomach when he saw it was empty.

He turned to move away, wondering where Casey might have hidden, when a tiny voice spoke up.

“Uncle Mikey?”

Mikey spun to see Casey, huddled beside the bed, a small pocket knife and his Jupiter Jim toy clutched in his hands.

Mikey didn’t know how he missed him, but he didn’t care.

Flying forward with his arms outstretched, he scooped Casey up, careful to avoid the blade. Where did he get that anyway?

“Casey! Are you ok? Are you hurt?”

“No, I'm ok!” Casey said. He let Mikey close the knife and take it, rubbing a hand under his nose as he sniffled. “I’m ok, but I heard all the yelling and Momma said to stay put if I didn’t know where she was and I wasn’t in danger. So I pushed my panic button like Uncle Donnie said and then sat here. But it was so loud, but I knew someone would come and then—“

A distant howl cut off his rambling and he grabbed Mikey’s scarf. Mikey tightened his hold on his nephew.

He spoke softly as he rose off the ground, rubbing Casey’s back. “Ok, I’m gonna get us to your dad, sound good?”

Casey nodded, pressing his face into Mikey’s neck and squeezing his eyes shut at Mikey’s command. Quickly looking around to ensure nothing was forgotten, Mikey tucked the knife and the toy into his belt before vanishing from the room.

Mikey hit the ground running, sprinting toward his brother’s portal, where Leo and Raph were beating back the remaining hounds.

“Raph! I got him!” He shouted, leaping over fallen Kraang bodies. Raph’s head whipped around, relief spreading across his face at the sight of Casey in Mikey's arms. Leo cut through another dog, his blades and markings beginning to glow. The portal pulsed brighter in response.

“Raph, go through!” The slider commanded.

Raph disappeared through the portal with a whoosh, Mikey right on his heels. Leo tumbled through after them, closing the gateway before any Kraang could follow.

"Dad!" Casey wailed, scrambling out of Mikey's hold the moment they landed, and racing toward his father as other members of the Resistance slowly gathered around them. Raph dropped to his knees and pulled him against his chest, bending over Casey so that his broad shoulders and arms blocked him from view.

Leo clapped a hand on Mikey's shell as he wiped his forehead, nodding to the worried crowd.

"You all good, little brother?"

Mikey sighed, the tension in his shoulders loosening as he watched Cassandra barrel through people to get to her son. "Yeah, all good."

Chapter Text

“Hey…um, Uncle Donnie?”

Donnie looked up from his circuitry. The Kraang attack and subsequent evacuation last week had been a fluke, thanks to dum-dums not checking their work properly. So he was currently working on expanding the distance that his satellites reached.

Donnie would not let the mistakes of others threaten his family again. But, he always had time for Casey.

“Yes, Casey?”

“Can I ask you a question?”

“But, of course! How may I help my favorite nephew?”

He set down his tools, gently pushing his tech away from the edge of the desk and dismissing his holographic goggles. He turned to face Casey, the 10-year-old shuffling his feet against the ground.

“Um…” Casey watched the ground intently and Donnie frowned. His nephew was not known for his shyness. He crouched so he was at Casey’s height and let his arms rest on his knees, trying to appear open and unintimidating.

“Casey?”

His nephew shrunk in on himself and Donnie’s worry spiked.

“I just, well, I wanted to ask…do you know why my hand’s doing this?” Taking a deep breath, Casey lifted his right hand up from where it was hiding behind his back.

Donnie blinked rapidly, before summoning his goggles back over his face. The settings of the lens zoomed in and out, as his tech frantically tried to focus on what he was seeing. Or rather, what he wasn’t seeing.

Because his nephew’s entire right hand was completely invisible.

Donnie stared at Casey. Casey stared at Donnie.

Then Casey yelped as Donnie grabbed him around the waist and hoisted him off the ground.

Casey blinked rapidly as his uncle gently sat him on a table before grabbing his invisible hand. Donnie spread Casey’s fingers, ran his own hand over his knuckles, and squinted at Casey’s wrist where his arm faded back into visibility.

As his uncle inspected his hand, Casey fought the urge to fidget, sitting on his other hand and tapping his shoes together, nervously.

His uncle’s eyebrows were furrowed with concern, but he didn’t seem too worried.

“Interesting,” Donnie said, gently playing with Casey’s fingers. “Your hand is still there, it’s just completely invisible. Casey, how did this happen?”

Casey frowned when his uncle looked at him with a raised eyebrow.

“Um…I don’t really know how…this whole thing happened.”

During the Kraang attack, when Casey had been stuck in his room, he had known that his family could come to save him after he activated his panic button. His mom had given him a little pocket knife, so he had pulled it out before crouching next to his parents' bed.

His family would come for him. He just had to hide until they got here. But they would come.

He remembered a warm feeling spreading out from his chest, all throughout his body, as he thought of his family. The warmth had comforted him, even as Kraang noises had increased from outside. Then the door opened, revealing Uncle Mikey.

But Uncle Mikey hadn’t seen him, his eyes had passed right over Casey. It wasn’t until Casey called out to him, that his uncle recognized him being in the room.

Casey hadn’t worried about it. Mikey was there and then they were with Dad and Mom and the rest of their family, and everything was fine, just like Casey knew it would be.

Casey hadn’t thought about why Mikey hadn’t seen him–even though he hadn’t really been hiding–until today. He had been thinking about it as he set up his new room, wondering if something had happened that made Mikey miss him.

Then he looked down and saw that his hand was invisible, the warm feeling returned.

Casey explained all this to Donnie, as his uncle shone a flashlight through his hand. Donnie hummed, clicking off the flashlight and tapping it against his chin.

“Well, it doesn’t seem to be affecting you in any negative way. Look,” he lifted Casey’s hand, “it’s already coming back.” And it was. Slowly, Casey’s skin was becoming visible again.

“I still want to do more tests. I wonder, is this something mystical? You did say that you were relying on us to save you when this warm feeling first happened. We should tell your parents,” Casey grimaced at the idea of his mom and dad worrying, as his uncle continued to ramble, “but my hypothesis is–”

The door slammed open.

“Yo, Tello! Have you seen Case—WHAT THE HELL?”

Donnie spun away from Casey, who turned fully invisible with a yelp, to face his twin.

Leo’s face was slack, his eyes blown wide. He looked a little ridiculous in Donnie’s humble opinion.

"Ummmmm ,” He squeaked, pointing at the place where Casey sat but wasn’t visible, “Donnie? What did you do to our nephew?”

Thoroughly insulted, Donnie sputtered, splaying a hand across his chest. “Wha— horrified gasp! Why did you think I did something!?”

“Well, maybe because Casey just vanished? Did you vaporize him!?”

Leo leapt forward, clambering over Donnie’s shoulders and reaching toward the table.

“Casey! Don’t worry, buddy! UNCLE LEO WILL SAVE YOU!”

“Nardo, get off! ”

Casey burst into giggles as his uncles wrestled. Leo’s head whipped up, bewildered.

“Casey!? Where are you, kiddo?”

“Um, right here, Uncle Leo.” Casey waved his hand in front of him. His smile faded as Leo’s eyes drifted over him.

Quickly, Casey glanced down. His hands and body were visible to him but strangely faded, covered in a light blue light. He looked up at his uncles, whose gazes kept missing him. His heartbeat was beginning to race.

His voice cracked. “Uncle Donnie?”

Leo leapt off Donnie’s back as Donnie darted forward. He reached forward carefully, tapping the desk lightly until he hit Casey’s leg. Casey immediately grabbed his hand and Donnie squeezed it.

“It’s ok, Casey.” He said firmly. “Can you tell me what’s happening?”

“Um, it's…it’s a little scary,” Casey whispered. Leo stepped forward, his hand also outstretched and Casey grabbed it too. “I can see you guys, I can see everything, even myself. But, it’s weird? I’m…shimmery? There’s like a blue light on me.”

“Leo,” Donnie said, pulling his goggles over his eyes, “can you go get everyone? Including Barry?”

For the first time that Casey could remember, his uncle didn’t respond with anything funny or clever. He just squeezed Casey’s hand and smiled at him, before hurrying out of the room.

Casey whimpered when Leo left and Donnie quickly tucked him against his side, a metal hand emerging from his shell to rub Casey’s back. Casey was horrified to feel his eyes well up with tears.

“Uncle Donnie? What’s wrong with me?” He sniffled.

“Nothing’s wrong with you,” Donnie said fiercely, his hug tightening. “We’re going to figure this out. My goggles detected mystic energy, so whatever this is, Barry or Mikey should be able to find a solution.”

“Promise?”

“I promise.” And Casey knew that Uncle Donnie never broke his promises.

“And look at it this way,” Casey looked up at his uncle as a mischievous smile spread across the turtle’s face, “If you’re able to control it, we can use it to prank Leo.”

Casey snickered and accepted the tissue that Donnie offered. He wiped his nose just in time for the door to slam open for the second time that day. Donnie winced as Cassandra burst into the room.

“WHERE’S MY BABY!?”

“Momma!” Casey shouted.

Cass sprinted forward, Raph hot on her heels, her arms opened wide enough to blindly grab Casey and pull him into a hug. The hug tightened as Raph joined and Casey let out a slow, relieved breath as his worry faded away.

Then his mother pulled back and glared at Donnie.

“Donatello! What did you do to my boy!?”

“Why does everyone assume I did something!?“

“Easy, Cass,” Raph said as he gently turned her away from glaring at Donnie. Then, after taking a deep breath, he stared at Donnie, his remaining eye wide and twitching slightly. “Hey, Don? Wanna tell me what’s up with my son?”

His voice was tight and very strained.

Donnie threw his hands into the air.

Chapter Text

Casey played with the edge of his dad’s cape while he watched his uncles and Jiji Barry talk in the corner. Uncle Mikey said something that made Uncle Donnie snap his fingers and point at him excitedly, while Jiji Barry rolled his eyes, despite the small smile on his face.

“Hey, Case. You doing ok?” Uncle Leo asked.

His dad shifted back a little so Casey could get a better view of Leo. Leo’s gaze was just a little too far to the left, but Casey knew he was trying to look him in the eye.

“I’m ok. A little hungry.”

“We can get food as soon as your uncles are done, baby,” Mom promised, carefully leaning down so she could kiss Casey on the head.

“Ok, Momma.”

“AHA! I knew it!” Uncle Donnie held his hands above his head in victory as he, Mikey, and Barry walked back to the rest of the family.

Raph curled his arm around Casey’s back.

“Donnie? What did you figure out?”

Donnie darted forward, his hands gesturing wildly in excitement.

“So, when Casey first showed me his invisibility, I thought that it might be some mutation or side effect of some tech, but when my goggles detected mystic energy, I began to wonder, ‘Is this something more?’ Now, you know I’m not a fan of the technicalities of mystic powers and magic, but—“

“Uh, Donnie?” April interrupted, casting an amused look at Cassandra’s confused and slowly darkening face. “Maybe we can skip the long explanation ‘til later?”

“Ah, yes, you probably want a fast answer—“

“Oh for goodness—young Casey has developed his mystic abilities. His invisibility, it’s from his ninpō.” Barry said, crossing his arms.

Donnie immediately deflated. “Aw, Draxum! I wanted to do the reveal!”

“Come on, Barry! Stop sounding so serious! You were excited over in the corner!” Mikey teased, poking his father’s cheek. Draxum let him.

Casey looked down at his hands, which were still fading in and out of visibility.

“My…ninpō?”

Donnie crouched in front of him, excitement glittering in his eyes.

“Remember when you told me about hiding during the Kraang attack? What were you thinking when that warm feeling first happened?”

“Um,” Casey wrinkled his nose as he tried to remember, “I was thinking that Dad or Mom or one of you was going to come get me soon. I was waiting for you.”

Raph and Cass’ eyes filled with tears while Mikey clung to April and Leo dramatically covered his face. Donnie smiled and one of his robotic arms patted Casey’s knee.

“You trusted in your family, Casey. That’s how we unlocked our ninpō. It makes sense that’s how you unlocked yours.”

“So…this is good?”

Donnie chuckled. “Yes, it’s good. It might take some getting used to and some training to help you use it properly, but it’s a power from our family. It’s meant to help you, and to remind you of your connection to all of us.”

Mikey floated forward, a large grin on his face, and gently pressed his palm against Casey’s chest. Warmth spread through him and Casey gasped when a greenish-white symbol appeared on Mikey’s chest.

The glow brightened as the symbol appeared on the rest of his family. Mikey pulled away with a smile and Casey looked down to see the familiar circle above his heart.

“Anatawa hitorijanai, Casey Jones-Hamato.” Leo said with a wink. He ruffled Casey’s hair as the symbol slowly faded away.

Then he stepped back as Casey’s mom and dad surged forward to wrap him in a hug.

Cass chuckled as Raph sobbed into Casey’s hair.

“Raph, love, you gotta breathe.” She said teasingly.

“Bu—but, Cass…our baby…he—he’s all grown up!” Raph wailed. Cass’ face fell at his words and her eyes also began to water.

Casey groaned as his mom’s hug tightened and suddenly both of his parents were sobbing messes. He patted their elbows.

“Ok then!” April said cheerfully, patting Cass on the back and handing her a tissue. “Dee, is there anything you can do to help Casey until he can control his power?”

“I’ll definitely look into it. But for right now,” Donnie moved so Casey could see him over his parents’ shaking shoulders. “Casey, please stay with one of us until you get a better grip on controlling this. I don’t want you to get lost or injured when we can’t see you. I’ve already changed the settings on some of my tech, so I will be able to detect you even when you’re fully invisible. Feel free to come to me if you ever feel uncomfortable with your powers and I’ll figure something out to help.”

“Thanks, Uncle Donnie,” Casey said, very relieved that his uncle already had a plan in place. “You’re the best.”

Donnie gasped and clutched at his chest.

“My nephew’s appreciation! It’s all that I’ve dreamed of!” He pointed at Leo. “I told you. I’m the favorite uncle!”

Casey giggled as Leo shrieked in outrage and attacked his twin as April cackled. Jiji Barry had already turned to leave the room and Mikey was hanging off his arm, laughing as he dug in his heels to try to get him to stay.

His parents were still crying on either side of him, but he didn’t mind.

He flexed his hands. They were visible again.

Squinting at them, he watched in wonder as the tips of his fingers briefly turned invisible.

“Cool.” He whispered.

His very own Hamato ninpō power. He was so excited to learn how to use it.

And Uncle Donnie was right. This was going to be great for pranks.

Casey was never going to lose a game of hide-and-seek ever again.