The dojo was buzzing with energy as Master Splinter stood before Mari, his hands clasped behind his back. She had been sidelined for too long, and now—finally—she was being cleared to rejoin missions.

"You have healed well, Marietta," Splinter said, his voice measured and firm. "But do not let your eagerness cloud your judgment. Strength is nothing without control."

Mari barely contained her excitement, rolling her shoulders as she grinned. "Got it, Sensei. No recklessness, no overdoing it." Then, her smirk widened. "Now—who wants to get their shell kicked?"

Leo sighed, rubbing his temple. "You just said no recklessness."

Mikey raised his hand. "I vote Raph!"

Raph scoffed. "Like I'd waste my time."

Before Mari could challenge him, Donnie—who had been watching from the side—straightened, clearing his throat. "I'll spar with Mari."

Mikey let out a dramatic gasp. "Ooooh, Donnie, trying to impress April!" He wiggled his fingers teasingly.

April, who was sitting cross-legged nearby, smirked. "This should be good."

Donnie shot Mikey a glare before stepping onto the mat, gripping his bo staff. Mari cracked her knuckles, her grin sharpening.

"Let's go, Brainiac," she taunted.

Splinter nodded. "Hajime."

Donnie moved first, spinning his bo and lunging forward, aiming for Mari's side.

Big mistake.

Mari sidestepped effortlessly, grabbed his extended arm, and yanked him forward. Before Donnie could react, she twisted, flipping him over her shoulder. He hit the mat hard, groaning.

Cat, who had been sitting off to the side, gasped dramatically. "Ohhh, Donnie, noooo! I can't watch!" She covered her eyes—only to peek through her fingers.

Mikey burst into laughter. "That was embarrassing!"

Donnie groaned, trying to recover, but Mari wasn't done. She grabbed his bo staff, yanked it from his grip, and twirled it mockingly. "You dropped this."

She tossed it back at him, and before he could catch it, she hooked her leg behind his and swept him onto his back again.

"Double embarrassing," Raph muttered, shaking his head.

Donnie rolled over onto his stomach, groaning. "I hate today."

Mari leaned over him with a smirk. "Thanks for volunteering."

Splinter clapped his hands together. "Yame! That is enough."

Donnie sat up, rubbing his head as Mari stepped back, stretching proudly.

Cat clapped excitedly. "That was so cool, Mari! You were like—" She mimicked Mari's movements with exaggerated sound effects. "Whoosh! Bam! Donnie had no chance!"

Donnie muttered under his breath, "I could have had a chance."

After training, Donnie stormed into the hallway, still rubbing his sore shoulder. "What the heck was that?" he demanded, glaring at Mari.

Mari, casually adjusting her yellow bandana, smirked. "What? Just having fun. You challenged me, remember?"

"That wasn't 'fun'—that was humiliating!" Donnie shot back. "April was watching!"

Mari scoffed. "Do you really think you have a shot with April still? Hate to break it to you—again—but you don't."

Donnie was about to respond, when April's voice cut through the chatter.

"What was that?" she murmured, staring at her laptop.

The turtles turned. April sat at the table, her brows furrowed as her laptop screen flickered strangely. A distorted, scrambled noise played from her speakers.

Leo leaned over. "What is that?"

April frowned. "I don't know. Some random email I got. It just started playing by itself."

Donnie, desperate for a distraction, immediately focused on the screen. His fingers flew across the keyboard as he analyzed the signal. "Sounds like some sort of telemetric sine wave subcarrier."

Leo blinked. "Uh... dumb that down a notch?"

Donnie adjusted his glasses. "It's an interference modulation used to encrypt covert transmi—"

Mikey clamped a hand over Donnie's mouth and shook his head. "Not enough notches."

Donnie pushed Mikey's hand away, exasperated. "It's a secret message!"

April's eyes widened. "Who would be sending me a secret message?"

Leo yawned as he stretched, rubbing the sleep from his eyes. The lair was still dim, the quiet hum of pipes and distant city sounds the only noise. He glanced around, noticing his brothers still sprawled out in their hammocks. Cat was curled up in hers, drooling slightly, while Mari was already awake, leaning against the couch, sharpening her tanto.

Something felt off.

Leo frowned. "Anyone seen Donnie?"

Raph groaned as he sat up, running a hand down his face. Mikey stirred next to him, mumbling as he pulled a crumpled popcorn bag off his head.

"Not since yesterday," Mikey mumbled. Then his eyes suddenly lit up. "Wait! Do dreams count? 'Cause last night, I dreamt Donnie and me were rodeo detectives, and there w—"

"Can it, Mikey. I'm serious."

Mikey huffed. "Okay, okay. But you'll never find out who stole the Buckaroo Diamond."

Leo stared at him, unamused.

Mikey sighed. "It was the clown."

"Wait, Donnie's missing?" Mari asked, finally looking up from her blade.

Leo nodded, concern creeping into his voice. "Yeah. I don't like it."

Cat stretched her arms with a yawn. "Maybe he just went on a nerd trip? Like, a midnight tech run?"

Leo ignored her and called again. "Donnie?!"

Nothing.

His unease grew. Donnie wasn't one to disappear without a word.

Raph swung his legs over the side of his hammock. "Check the lab."

They hurried inside, but the lab was empty. Leo's stomach tightened.

"Guys, I think I know where Donnie went," Mikey said suddenly, his voice more serious.

Leo turned. "Where?"

Mikey pointed at Donnie's laptop, the screen still glowing.

Raph squinted at the monitor. "Oh. There."

Leo leaned in, eyes scanning the message on the screen.

"That's the secret message," he murmured.

"Obviously, he followed it," Raph added.

"After he figured out what it was."

Mikey's expression turned anxious. "What would Donnie do? What would Donnie do?"

Raph rolled his eyes. "Gimme that thing!" He grabbed the laptop, shaking it slightly.

"Raph!" Leo shot him a glare before yanking the laptop away.

The screen flickered as the message played again.

"April, it's Dad. I pray you get this message. I've been moved to a secret Kraang facility."

April's voice broke through the moment, soft but filled with disbelief.

"...Dad?"

Silence fell between them.

Leo's fists clenched.

They had to find Donnie. And fast.

Lasers cut through the darkness, illuminating the metallic walls of the Kraang facility. Donnie darted between them, his staff spinning as he deflected incoming fire. His breath was steady, but his mind was racing. He had to keep moving. He had to find April's dad.

Meanwhile, miles away, Leo, Raph, Mikey, Mari, and Cat sprinted across the rooftops, their silhouettes flashing against the city skyline.

Leo's voice was sharp with frustration. "Why would Donnie try to rescue April's dad by himself?"

Mari, who had been running just behind him, sighed. "Because I told him he had no shot with April."

Raph let out a low whistle. "Wow. Day one back, and you already made our brother feel the need to take a solo mission? Nice going, Mari."

Mari rolled her eyes but didn't respond, though there was a hint of guilt flickering in her expression.

Leo groaned. "Seriously? Why would you tell him that?"

Mari huffed. "Because he doesn't have a shot with April."

Leo threw his hands up. "Well, yeah, but you don't tell him that."

Mikey, ever the peacemaker, sighed dramatically. "The heart's a soft muscle, man. A soft muscle." He clutched his chest for emphasis. "Squish."

Cat, who had been quietly keeping up, tilted her head. "That was mean, Mari."

They picked up their pace, the wind rushing past as they leapt from one rooftop to the next.

The five turtles came to a stop outside a dimly lit garage. The metal door loomed before them, silent and still.

Raph glanced around. "You sure this is the right place?"

Leo nodded. "Either Donnie's here... or the garage mechanic stole his lock pick."

Mikey gasped. "So the mechanic could break into his own place?" He shook his head, as if the very idea was ridiculous. "Come on, Leo, think this stuff through, dude!"

Mari rolled her eyes. "Pretty sure Donnie's the only one who thinks this hard about breaking and entering."

Cat, meanwhile, was looking around nervously. "Okay, but what if this isn't the right place and we just, I don't know, break into some random garage?"

Leo deadpanned. "Let's move."

Mikey pointed. "See? That's how you say it."

Leo sighed before pulling the garage door open.

Mikey grinned. "Yeah!"

Raph smacked him on the back of the head. "Punk."

The space was dimly lit, littered with spare parts and abandoned equipment. A Kraang droid lay slumped against the wall, motionless.

Raph nudged it with his foot. "Pretty sure Donnie took this guy out."

Leo crouched beside it. "How can you tell?"

Raph smirked. "He looks bored to death."

From behind them, Mikey let out an excited whoop. "Hey, guys! Check out my ride!"

They turned just in time to see Mikey sitting behind the wheel of an old, dusty car.

"Mikey, no—"

Before anyone could stop him, Mikey slammed his foot onto the pedal. The car lurched forward, sending Leo and Raph scrambling out of the way. The impact triggered a loud mechanical clunk! and, suddenly, a hidden entrance slid open.

Leo blinked. "...Nice, Mikey."

Mikey smirked, spinning the wheel dramatically. "Oh, yeah."

Raph scowled. "Do not say 'I meant to do that.'"

Mikey opened his mouth—then thought better of it.

Mari rolled her eyes. "You are so lucky that actually worked."

Cat peeked inside the darkened entrance. "Are we sure Donnie's in there and not, I don't know, something worse?"

Leo motioned forward. "Let's move."

They slipped inside, their steps quick and cautious. The facility was eerily quiet, save for the occasional drip of leaking pipes. It didn't take long before they spotted the remnants of a battle—discarded Kraang droids littered the floor, sparks still flickering from their damaged wiring.

Raph cracked his knuckles. "He must've gone through this door."

He stepped forward, gripping his sai, ready to break it down—

Leo grabbed his wrist. "Again—what would Donnie have done?"

Raph hesitated.

Mikey stroked his chin. "Hmm... Oh! I got it!"

The five turtles turned to a Kraang droid standing guard. Without hesitation, they rushed forward, ramming into it full force—

The moment the droid hit the ground, alarms blared.

Mikey's expression twisted into panic. "Boy, Donnie's idea was terrible!"

A monotone, robotic voice echoed from the halls.

"Why is that which is called alarm sounding that which is called the alarm?"

A second voice responded, just as mechanical. "Something which is not the plan is occurring."

Leo's grip on his katana tightened. "We've got company."

From the shadows, Kraang droids began to emerge, weapons raised.

Raph grinned. "Finally."

Mari twirled her tanto eagerly. "About time."

Cat, gripping her tessen, gulped. "I really don't like this part."

And with that, they charged.

The turtles moved swiftly through the dimly lit corridors, their senses on high alert as they searched for Donnie. The eerie silence of the Kraang facility was unsettling, each metallic clang echoing ominously.

Leo's grip on his katanas tightened. "I don't like the sound of that."

Mikey, ever the optimist, waved a dismissive hand. "Maybe if we ignore it, it'll go away."

A deep, guttural growl rumbled through the halls.

Mikey paled. "Someone's not ignoring it."

Before they could react, an explosion erupted, forcing them to dive for cover. A massive, reptilian figure emerged from the smoke, eyes glowing with fury. It was unlike any Kraang droid they had faced—bulky, armored, and armed to the teeth.

The creature raised its weapon, the barrel glowing ominously.

"Move!" Raph barked.

The turtles scattered as a blast of energy tore through the hallway, leaving a smoking crater where they had stood.

In the control room, Donnie worked frantically at the panel, his fingers flying over the keys as he tried to decode the scrambled transmission. "Okay, if I jump the resistors—"

Boom!

"Donnie!" Raph's voice rang out, echoing off the metal walls.

They came face to face with Kirby.

"April's dad?" Cat questioned. "Where's the big beady lizard thing?"

"Donnie calls it the neutralizer," he says.

A deafening explosion rattled the building, and the ground trembled beneath him.

Before Donnie could look up properly, the door burst open. Leo, followed by Kirby O'Neil, stormed in. In their wake, Donnie saw Mikey's eyes narrow as he glared at the scene.

"You named something without me?" Mikey snapped, his tone half-amused, half-betrayed as he pointed dramatically at the control screen.

Donnie blinked in confusion. "What?"

Mikey shook his head. "You named something without me? Seriously?"

Mari, who had been standing near a console with her arms folded, rolled her eyes. "Not the time, Mikey."

At that moment, the door shook violently as a menacing presence slammed against it from the other side. Leo pulled his attention away from Mikey's melodrama. "We gotta get out of this prison," he said, his voice gruff.

Kirby, ever the scientist, corrected matter-of-factly, "Technically, this is a detention center—the difference being that—"

"Not now, Donnie!" Raph interrupted abruptly before glancing at Kirby with a sheepish expression. "Uh... sorry, Mr. O'Neil."

Leo sighed. "Great. Now there's two of them."

A metallic clatter sounded behind them. The turtles turned as a squad of Kraang droids marched into view from the opposite hall, weapons raised and lights flashing ominously.

"Little help here?!" Mikey called out as the enemy advanced.

Donnie barely looked up from the console. "How about some big help?" he replied, exasperated.

Leo frowned. "Not really the time to check your email, Donnie."

Donnie's fingers danced over the keys, and the security feed flickered. The monitor revealed a massive, hulking creature locked in a containment chamber.

"I'm guessing if they had the Newtralizer locked up, it wasn't because he was their friend," Donnie said grimly.

The moment he hit the override, a mechanical hiss echoed through the facility as the reinforced doors slid open with deliberate menace. Out stepped the Newtralizer—its reptilian form and glowing eyes a terrifying sight.

Leo's grip on his katana tightened. "We got company."

Raph grinned darkly. "Apparently, he likes trashing Kraang."

Cat's face lit up in a mischievous smile. "Who doesn't?"

At that moment, Donnie's console beeped urgently. The tension in the room soared. Kirby muttered something about protocol as the Newtralizer began firing its weapon.

Before they could fully react, Mari and Cat exchanged a glance. Mari's tone was curt and decisive: "We've got to move!"

Cat added in a breathy, almost playful manner, "Yeah—unless you want this detention center to be our new home."

As alarms blared and the droids closed in, Leo barked, "Let's split up!"

Donnie's fingers flew over the keys as he unlocked the door. "Donnie, you get Mr. O'Neil out of here," Leo ordered.

Mari scoffed, "I bet the Newtralizer will soon regret interrupting our little reunion."

Mikey, already by the door, raised an arm. "But what about us?"

Raph grinned. "We're not exactly a friendly bunch for the Kraang."

Donnie took a deep breath. "All right—let's move!"

The Kraang droids didn't stand a chance. The Newtralizer's blasters tore through them with ruthless efficiency, each blast sending debris flying. Sparks flickered in the air, illuminating the chaos unfolding in the dimly lit facility.

The turtles had no intention of sticking around to see if he was equally hostile toward them.

"Move, move, move!" Leo barked as they sprinted toward the nearest exit.

Behind them, Mari slashed through a Kraang droid with her tanto, her breathing ragged. "You think we should've left him in that cell?" she shouted over the explosions.

Cat, gripping her tessen, skidded to a stop as a Kraang arm twitched beside her. "I mean—maybe? But also, wow, he's really good at this!" she yelped as another blaster shot barely missed them.

Raph threw his arm in front of them, shoving them forward. "Less talk, more running!"

They reached an elevator, scrambling to take cover from the destruction behind them.

"Close one, huh?" Donnie panted, reaching for the control panel.

Raph wasted no time. He yanked out his sai and wedged them into the panel. "I got it!"

Donnie slapped his hands away. "Raph. I got it."

Raph raised an eyebrow. "Oh, really?"

Before Donnie could respond, Mari smirked, stepping up. "Oh, for the love of—move." She flipped a switch, and the panel powered up instantly, unlocking the elevator doors. She shot Raph a cocky grin. "Really."

Raph scowled. "You know, I liked it better when you were sidelined."

Mari rolled her eyes. "Too bad. I'm back, baby."

Before they could celebrate, another explosion rocked the facility. The Newtralizer was far from finished.

Leo barely hesitated. "Let's split up! Donnie, get Mr. O'Neil out of here!"

Donnie nodded, grabbing Kirby's arm. "Come on, sir—"

Just then, Cat let out a startled yelp as a Kraang droid twitched at her feet. "Oh, nope, nope! I'm leaving, I'm leaving—"

Donnie threw a smoke bomb to cover their escape as Leo, Raph, Mari, and Mikey turned back toward the raging battle.

Mari twirled her tanto, her grip steady. "Well. Guess it's our turn."

Mikey cracked his knuckles, grinning. "Man, I love when we do dramatic exits."

Leo exhaled sharply, adjusting his grip on his katana. "Then let's make it count."

And with that, they charged back into the chaos.

Leo, Raph, Cat, Mari, and Mikey turned to face the Newtralizer.

"Let's do this," Raph muttered, spinning his sai.

Mari cracked her neck, gripping her tanto. "Finally. A real fight."

Cat, gripping her tessen tightly, let out a nervous laugh. "Uh, define 'real fight'—'cause I feel like we're about to be vaporized."

The Newtralizer roared, raising his weapon.

Leo and Raph lunged first, engaging the beast in a fierce melee. Mari followed suit, ducking under a blaster shot before slashing at his leg. The Newtralizer barely flinched, swiping his tail and sending her stumbling back.

"Okay," Mari huffed, regaining her stance. "That's annoying."

Cat darted to the side, opening her tessen and flinging it at the creature's face. It struck his snout, making him snarl in irritation, but barely did any damage.

"Uh-oh," Cat muttered as the Newtralizer turned to her with glowing, angry eyes.

Before he could retaliate, Mikey leapt onto his back, wrapping his arms around the Newtralizer's head. "Ride 'em, cowboy!" he whooped.

It didn't last long. The Newtralizer snarled, reaching back and grabbing Mikey before hurling him across the garage.

"Mikey!" Cat yelped, racing to where he crashed.

Leo and Raph tried to double-team the creature, but a well-placed energy blast sent them tumbling. Mari charged again, slicing across his arm, but he backhanded her into the ground.

"Gah!" she groaned, pushing herself up. "I hate this guy."

Cat helped Mikey to his feet, her eyes darting nervously between him and the towering Newtralizer. "Plan B? Someone yell 'plan B'!"

Mikey groaned, rubbing his head. "Ow..."

The Newtralizer loomed over them, gun charging—

VROOOOOM!

A loud engine revved, and before anyone could react, a car smashed into the Newtralizer, sending him crashing into a pile of debris.

Mikey popped his head out of the driver's seat, grinning. "BOOYAKASHA!"

Leo, Raph, Cat and Mari stared.

"Mikey?!"

Mikey beamed as he climbed out. "Don't worry! I wore my seatbelt."

Raph shook his head, exasperated. "Come on."

Cat, wide-eyed, pointed at the crumpled mess of debris. "You guys saw that, right? Please tell me we don't have to fight him again."

Mari rolled her eyes, lightly pushing Cat forward. "Move it before he gets up."

April sat cross-legged in the dojo, her fingers lightly tracing the smooth surface of the strange, glowing orb. Its eerie hum pulsed softly, filling the room with an unshakable sense of unease.

Splinter watched her carefully, his brow furrowed. "Hmm... interesting. But I am curious—how is it that you can hear the sound while I do not?"

April glanced up, her fingers tightening around the orb. "Maybe... maybe this is why the Kraang are after me."

Before Splinter could respond, the sound of hurried footsteps echoed through the lair. The turtles and their sisters burst in, panting from their mission—but they weren't alone.

April's eyes widened in disbelief as she spotted the familiar figure among them.

"Dad?"

Kirby barely had time to register her presence before April rushed forward, throwing her arms around him. "Dad! Dad!" Her voice trembled, overwhelmed with emotion. "I can't believe it! You guys saved my dad!"

She turned to the group, gratitude shining in her eyes. "Thank you so much."

Raph, leaning casually against the wall, smirked. "The guy you really should be thanking is Donnie."

Donnie's face instantly flushed. "Well, I—"

Mari, standing next to Raph, gestured dramatically at Donnie. "No, seriously. It was insane. Our resident geek turned into a full-blown action hero. We're talking movie-worthy stuff here."

Raph nodded. "We kept saying, 'Careful, Donnie, it's too dangerous.' And Donnie was like, 'Danger? Ha! Nothing'll stop me!'"

Mari smirked. "Pretty sure he made that exact face too."

Donnie groaned, rubbing his face. "Wow, thanks, guys. I love this version of the story."

Cat, perched on the arm of the couch, grinned.

Donnie sighed, but before he could say anything else, April stepped forward, her expression soft.

"Thank you, Donnie."

Then, without warning, she hugged him.

Donnie let out a strangled noise—somewhere between a gasp and a squeak—before his brain completely short-circuited. His knees buckled, and he collapsed onto the floor, a dazed grin plastered across his face.

Mari facepalmed. "Oh my god."

Raph crossed his arms, smirking. "And there it is. Back to normal."

Cat giggled, leaning over Donnie. "Hey, do we need to get you a pillow? Maybe a fainting couch? Should I get the smelling salts?"

Mikey snickered. "Dude, I'd say you hyped him up too hard. He just could not handle it."

April held onto her father, relief washing over her like a tidal wave. "It's good to have you back."

Kirby smiled, wrapping his arms around his daughter. "It's good to be back."

But as he embraced her, his expression flickered.

His eyes—once warm and filled with relief—flashed an unnatural, glowing red.

And for just a moment... he stared directly at the camera, his gaze cold, calculating.

Unbeknownst to the turtles, their victory wasn't as complete as they believed.

Because Kirby O'Neil... was still under the Kraang's control.