All alone at the entrance of the lair, Leo stayed hidden in the darkness, waiting. He was positive that the rat would return to his home when there is nowhere else to go.

However, hours had passed and, not only did the rat not return, but neither did the other turtles. Leo began to wonder if the rat had captured and freed them from Shredder's control.

Just then, he heard a noise, like someone was scratching their claws on the ground. Leo turned to see a shadow disappearing around the corner.

A shadow that was in the form of a giant rat.

Taking his katanas out, Leo ran after the mutant rodent.

Once he made it around the corner, however, the shadow was completely gone. Leo scanned the area, suspicion rising within him.

His eyes spotted a manhole above him, discovering that it was open. That must be where that rat went, Leo thought to himself. Placing his swords back in his sheaths, Leo climbed up the ladder and through the manhole, entering into the surface of New York.

The road was empty and quiet under the blank, night sky, with only the full moon looking down from above. No humans were in sight; all the stores on both streets were closed.

Leo's eyes scanned the neighborhood, seeing no trace of the mutant rat.

Then, he heard that scratching sound again.

Leo spun around just in time to see the rat's shadow vanishing in an alleyway.

Leo instantly sprinted to the alley and, once he had entered, he paused.

Standing in the middle of the alleyway was the rat himself. His body was calmly still, his eyes closed as if he was meditating while standing up.

Leo studied him carefully. This can't be this easy; the rat must have a trick up his sleeves, a crafted plan to trap Leo inside that head of his. But Splinter just stood there, completely unarmed.

Suspicion was now blazing inside Leo's mind, but his duty to the Shredder was too important for him to care. Leo must complete his mission and destroy Hamato Yoshi.

Slowly drawing his katanas, Leo gradually moved toward Splinter, keeping his narrowed eyes on the rat.

But then, Splinter's eyes opened and they stared straight at Leo. Leo stopped once he was almost in front of the rat.

"Do you still wish to kill me?" Splinter finally spoke. His voice was no longer filled with depression and desperation. It seemed much quieter, with a hint of sorrow in it.

A malicious grin came over Leo's lips. "Oh yes . . . so much."

With his hands tightening on his swords, the evil turtle charged forward, going for the kill. But Splinter suddenly leaned back, just in time to miss the swords. Once the katanas chopped through emptiness, Splinter did a backflip and stood up, standing in a fighting position.

Leo groaned. "Not this again! Just let me kill you and we'll all be happy!"

He goes to slash his swords at Splinter again, but the rat carefully avoided them. Leo tried stabbing him again and again, but the rat evaded them every single time, to the point where it seemed like the rat was now taunting him (though Splinter kept his face blank the whole time).

All of a sudden, Leo heard a faint sound above him; the sound of banging against a metal. He looked up and almost caught a glance of a shadowy figure on the fire escape.

Before Leo could comprehend what was going on, Leo felt a pinch on his nerve point between his neck and shoulder, causing him to flinch and collapse, dropping his katanas.

Leo tried to get up, but he was abruptly pushed down by three bodies, trapping him on the ground. He turned his head to see the three turtles on his back.

"Don't move," Raph warned him, taking a firm hold on Leo's arms and pulling them on his back shell. "You're not getting away that easily."

Leo growled. So the rat has freed them from Shredder's mind-control. His mission has failed, then. Leo struggled harshly to escape, but to no avail.

"Don't worry, Leo," Mikey assured him. "We'll free you from the Pink Metal Bug as soon as possible."

There was a very brief moment when Leo paused to frown at the name.

"Easy," Donnie said to Leo as he leaned over to Leo's back neck. "Don't move."

But this only caused Leo's body to ferociously thrash, and the turtles tried desperately to keep their grip on him.

"Leo, stop! I'm trying to help you," Donnie attempted to say. But all Leo did was snarl savagely at him, the possessed turtle wriggling with all his might.

Splinter came to their aid, saying to Donnie, "Donatello, I will hold him down. Go and help your brother. Quickly!"

Nodding, Donnie got off of Leo and Splinter instantly took his place over his mind-controlled son. Now free, Donnie went over to kneel in front of Leo and pushed Leo's head down for him to see his brother's back neck.

To Donnie's complete shock, he found Leo's neck bare.

"What are you waiting for, Donnie," Raph shouted, slowly losing his grasp on Leo. "Take that thing off of him!"

Donnie took another look at Leo's back neck, but he found no mind control device there. His eyes frantically scanned over Leo's head and his back (or as much as he could see from under Leo's shell).

"What is the matter, Donatello," Splinter asked, taking note of Donnie's increasing panic.

"It . . . it's not there."

"What?" Raph and Mikey yelled in shock.

But, because the two were distracted, their hold on Leo lessened and Leo immediately took the chance to push the three off of him. He jumped high up and swiftly landed on the fire escape above the group.

Leo looked down at them, chuckling sinisterly. "Surprised?"

The group stared at Leo in alarm, not wanting to believe what it meant.

"Wait, you . . ." Raph started. "You were you the whole time?!"

"No," Donnie shook his head in desperation. "That's impossible!"

"Leo?" Mikey spoke with a broken voice.

Both he and Splinter stared at Leo, their eyes teary with heartbrokenness.

"Oh, but it is possible," Leo gleefully replied, jumping off from the fire escape and landing in front of the group. "I've gone to the dark side, and I couldn't be happier."

"That device has got to be on you!" Donnie anxiously shouted, his eyes hurriedly skimming over Leo's body for any sign of the device. "It has to be!"

Knowing what Donnie was doing, Leo gave a spin around to showcase his body, enjoying the misery he was giving to them at seeing no mind-control device on him. "Nope. Just me."

Finally, Splinter stepped forward, looking furious. "No! I will not believe this! The real Leonardo is somewhere deep within you."

"I am the real Leonardo!" Leo screamed angrily at Splinter. "I am now Shredder's loyal follower! And you are going to die, rat!"

Roaring, Leo rushed to pick up his katanas and charged straight after Splinter. No one in the group made an attempt to step away, too devastated to move.

That is, until one of them unexpectedly did move.

Without thinking, Mikey pounced in front of Splinter and threw a smoke egg right at Leo's face.

Leo shrieked in pain as the smoke from the crushed egg touched his eyes. He dropped his swords to clutch his eyes, feeling incredible agony.

"Sorry, Leo!" Mikey said, genuinely apologetic.

Now that he is defenseless, and knowing that he will be easily captured if he stayed longer, Leo ran out of the alley and into the streets.

"Leo!" the three turtles called after their brother, racing after him. But Leo was long gone by the time they've reached the empty road.

"Come on," Raph shouted to the others. "He could be heading back to the Shredder! We gotta go catch him!"

"No," Splinter's voice stopped them. His voice was now tired and awfully old, as if he had grown older in the past several hours. "Let him go."

"But Master Splinter," Donnie said. "Leo knows where we live! We have to stop him before he goes to tell the Shredder."

"What is to say that Leo hasn't already told the Shredder?" Splinter then sighed miserably. "We must return home and pack, before they find us. Come."

Splinter goes to mournfully walk toward the manhole, his energy fading away with every second. The three turtles exchanged apprehensive looks among themselves, very hesitant.

However, they obeyed their sensei and followed Splinter down the manhole, feeling far worse than ever before.

"I still say Leo's being controlled," Donnie insisted again, pacing in the living room.

When they got back, Splinter went straight to the Dojo room and the turtles hadn't seen him since. The three of them tried to pack, but their thoughts were too consumed with Leo and him betraying them.

So, taking a break, they hung out in the living room, hoping that it would help ease the ache over losing Leo.

It didn't.

"But you saw it," Raph argued at Donnie, feeling more angry and hurt than he could ever remember. "That thing wasn't anywhere on his body! He went and joined the Foot's side, Donnie! He went to join the Shredder!" He punched the dummy so hard, the dummy flew right across the room.

"But logically, it is impossible for Leo to turn around in just a short amount of time," Donnie tried to explain. "He was captured in less than an entire night. How do you become evil in those few hours?"

"Well, Leo did!" Raph shouted at Donnie.

"There has to be a reason, Raph!" Donnie kept persisting. "He's still our brother!"

"That turtle is not our brother!" Raph screamed at Donnie's face. "As far as we know, the Leo we know is gone for good!"

Donnie opened his mouth to retort, only to fall silent when his eyes caught something. Raph turned to Donnie's direction.

There, on the couch, was Mikey, sitting in a fetal position. He was awfully silent, lost in his thoughts of unhappiness.

"Poor, Mikey," Donnie lowered his voice so only Raph could hear him. "It's been a very rough night for him."

Raph's face softened at the sight of his little brother. He walked over to Mikey and sat down next to him.

"Hey," he gently said to Mikey. When, Mikey didn't respond, Raph lay his hand on Mikey's shoulder. "You ok?"

Mikey only buried his head on his knees, hiding his glistening eyes.

Raph sighed. His eyes fell to the ground as if searching for words to comfort Mikey.

"Hey, you know," Raph struggled to say. "Maybe . . . maybe Donnie's right. Maybe Leo's still under mind-control."

Of course, Raph didn't believe this, but it seemed to do the trick as Mikey pulled his head up to look at Raph.

"You really think so," Mikey asked him, hope glittering in his eyes.

Raph hesitated, but then smiled. "Yeah, sure I do."

Mikey's eyes suddenly widened. "Hey, what if that evil Leo isn't the real Leo at all?"

"You mean that there's a shape-shifting mutant posing as Leo," Donnie helpfully suggested, walking over to join his brothers. "Or a Kraang in a robotic body suit disguised to look like Leo? That's very likely."

"No!" Mikey stood up to face his brothers, eagerness flashing on his young face. "I mean the evil Leo is actually . . . a giant pink metal bug!"

Raph and Donnie both frowned at Mikey.

"Hear me out," Mikey said. "What if the Kraang built a life-size Metal Bug and dressed him up as Leo!"

"Like a Kraang in a robotic body suit disguise to look like Leo," Donnie said in monotone.

"No, it's not the same," Mikey insisted. "I bet that the Kraang made the giant metal bug and put Leo's brain inside of it, so Metal Bug would know everything about us!" Mikey suddenly gasped. "Oh, no! We gotta go save Leo's brain!"

Mikey goes to run off, but Raph immediately went to grab hold of Mikey's shell and pulled him back, causing Mikey to fall back on the couch.

Raph glanced at Donnie and shrugged. Well, at least Mikey's not depressed anymore.

"Hey guys," a cheery voice suddenly interrupted the turtles. The three of them turned to see April entering the lair. Donnie instantly blushed at the sight of her.

"Hey April," each of the turtles greeted her.

Taking note of the packed boxes scattered around the living room, a confused April asked, "Uh, what did I miss?"

Raph looked away, fury starting to return to him. However, he stayed silent for Mikey's sake.

Donnie sighed. "It's a long story."

Then April noticed something. "Where's Leo?"

Raph and Donnie looked hurt, but Mikey instantly answered her.

"He got kidnapped by Shredder, and now Metal Bug is posing as Leo and he wants to kill us all," Mikey said it in one breath.

It took a moment for April to speak. "Wait, what?"

Raph gave Donnie another look that didn't want Donnie to tell the story in front of Mikey. They really didn't want Mikey to fall back into depression (even though he was quickly getting irritating).

"C'mon," Donnie said to April. "I'll explain everything in the lab."

Baffled, April followed Donnie out of the living room, leaving Raph to listen to Mikey break into another silly rant.

Once alone in his lab (the one opportunity that Donnie had always dreamed of, but was too preoccupied to savor it), Donnie began explaining everything to April.

When Donnie finished his story, April looked completely flabbergasted.

"Wait," April said, trying to comprehend what she had just heard. "Leo turned evil? Just like that?" Donnie nodded. "That doesn't sound like him."

"That's what I thought. But there is no sign of any mind-control device on Leo's body. Believe me, we've looked."

"Well," April said, trying to think of possible solutions. "Maybe it's hidden in the one place where you can't see."

"And where would that be?"

"I don't know, inside his body?"

Donnie opened his mouth to reply, only for his eyes to widen, a brilliant discovery sparking in his brain.

"That's it," Donnie suddenly said, his voice rising with excitement. "That's it! April, you're a genius!"

Donnie went to hug a perplexed April (making a mental note to himself to bang his head against something hard for it later). He pulled back and gripped onto April's shoulders. "Tell the others not to leave the lair just yet! I'll call you guys when I'm done!"

April tried to ask what was going on when Donnie started zealously pushing her out of the lab.

"Just give me twelve minutes!" was the last thing he said to her before Donnie closed the door right behind her.

April looked back at the door, not sure if she should be outraged that he had technically kicked her out or not.

She turned around to meet Raph and Mikey looking at her.

Then Raph asked, "Do I need to know what happened in there?"

It was actually five minutes later when Donnie finally called everyone to come in the lab.

The group was so far lucky that no alarms had gone off, indicating that the Foot soldiers were in the sewers. Splinter had come out a minute ago and demanded to know why the turtles weren't packed up yet, until Donnie started calling for everyone to enter into his lab.

"Guys, I just figured out why Leo is behaving the way he is," Donnie started with delight.

"Metal Bug!" Mikey exlaimed.

Raph groaned.

"Actually," Donnie said, smiling. "Mikey's right."

Raph looked at Donnie with astonishment, while Mikey smugly grinned at Raph.

"Just not in that way," Donnie added, which caused Mikey to drop his grin.

"What are you talking about, Donnie," April asked.

"It's just what you said earlier," Donnie answered to her. "Inside. There are other ways to control a victim, so long as it's connected to the brain. So, I believe that the mind-control device is actually attached to Leo's brain."

"Wait, how can a thing that big get through his skin and to his brain," Raph asked, glancing at a tray nearby them, carrying three big mind-control devices that had been attached to the three turtles. None of them looked like they could seep through any body.

"Leo swallowed one," Mikey suggested.

"Not really," Donnie told him. "If you swallow it, it wouldn't go straight to the brain; just the stomach. No, the Kraang must have created a much smaller version of their mind-control device and Shredder had it inserted through Leo's skin and up to his brain."

"Ok, great," Raph said, scowling. "We know it's inside Leo's body. So, how do we destroy that piece of junk from the inside?"

"Oooo, are you going to shrink us and place us into a tiny submarine and put us inside Leo, so we can journey to Leo's brain and destroy it before we grow back to normal size," Mikey animatedly asked Donnie.

Donnie stared at Mikey for a moment. "Uh . . . no. I basically inject this into Leo's body." He held up a syringe that was full of brown liquid.

"Chocolate milk?" Mikey said, gazing curiously at the liquid.

"It's a nontoxic liquid that will mix into Leo's bloodstream without affecting his blood," Donnie patiently explained. "But it's what's inside this liquid that will destroy the device."

The group looked at Donnie, perplexed.

Donnie confidently directed them to a microscope, placing the syringe underneath the lenses. "Take a look," Donnie encouraged them.

April was the first to look through the eyepiece. She gasped at the sight. "It's a mini submarine!"

April stepped aside to let Mikey have a turn. "Wow," Mikey exclaimed. "You already shrunk it! It looks so tiny!"

"I didn't shrink it, Mikey," Donnie said as Raph slightly pushed Mikey aside to let himself have a look. "I've been working on it from my success at the cockroach mini spy." Raph flinched. "I have recently placed a miniature torpedo on the submarine to destroy the mind-control device. To control the submarine, I've found and reconstructed this." Donnie pulled out a small device that he flipped open to present to the group.

April's eyebrow rose. "Is that a Nintendo DS?"

Donnie looked genuinely surprised. "Is that really what it's called?"

"Ok, so we found a way to destroy that bug on Leo's brain," Raph interrupted, his voice full of impatience and pessimism. "But there's still a problem on getting that submarine inside Leo. What are we going to do, ask him nicely to take a shot?"

Donnie glared at Raph for a second. "No, I actually have a plan. But . . ." Donnie looked down, hesitating. "It might be risky. And . . . it might be too much to take for us."

A pause flowed through the lab.

"Donatello," Splinter finally spoke, surprising the teenagers, briefly forgetting that Splinter was still here with them. "Will this plan of yours . . . work?"

Donnie sighed. "It's all I can come up with at this moment. Master Splinter, we'll need you to distract any foot bots that come in the sewers. April, you're with us. Now, all we need to do is find Leo."

"I think I know a way to direct Leo to us," April said, smiling.

By the time the pain on Leo's eyes faded away, he quickly noticed two things. One, almost seven minutes had passed, and two, he had been unsuccessful on his mission.

Failure weighing over him, Leo returned to the Shredder's lair to report what had happened.

And Shredder didn't take the news very well.

"AHHHHHHHHHHHHHH!" Shredder shrieked in pure rage, slashing his blades through every Foot Ninjas there, chopping each of them into pieces around him. His two anxious mutant servants stood to the far side to avoid Shredder's death slice. Karai stood farther away from her father, lost in her own anger over the fact that Splinter was still alive.

All the while, Leo stayed kneeled before Shredder, waiting patiently.

"WHAT DO I HAVE TO DO TO BE RID OF HAMATO YOSHI?!" Shredder shouted, decapitating two more Foot Ninjas. One head rolled up in front of Fishface and Razahr, who both frightfully stepping further back until they were up against the wall.

At last, Shredder stopped, heavily panting from massacring his numerous foot soldiers, their remains littered at his feet. "I can't wait any longer. Bradford! Xever!"

Nervously, Razahr and Fishface stepped before Shredder, their heads hanging low to avoid showing fear to their master.

"Take as many of my ninjas as you can and search the sewers! When you find the rat, bring him to me alive! I want to finish him off myself! Do not fail me!"

Gulping, the two nodded. "Yes, master."

Shredder then returned to Leo. "As for you . . . you may still be of some use to me. Are you still loyal to me?"

Leo looked up, narrowed at the Shredder. "You're wish is my will, my master."

Shredder smiled evilly under his mask. "Then there is a chance you can redeem yourself. Hunt down the other turtles . . . and destroy them all."

Leo's lips grew wider with wickedness. "As you wish."