Leo was one with the universe. Or at least he was trying to be. Deep breath after deep breath, unwanted thoughts kept pressing their way into his mind. Let them flow over you, he mentally instructed himself. Acknowledge, and let flow.

The thoughts, however, were not content to be acknowledged and released. They buzzed around his head like flies, biting him, refusing to leave him alone.

If he ever needed to draw strength from the universe, it was now. He had to gain control of his inner self, so that he could lead his family and save his brother. But his attempt to meditate was hopeless. With a heavy sigh, he opened his eyes and returned to the present.

Splinter was standing in front of him. Leo yelped in surprise.

Splinter cocked his head. "Either you were in a deep trance, or you are extremely distracted. I did not make any effort to approach you quietly."

Standing up, Leo stretched his legs. "I wasn't in a trance, Sensei."

"I know."

Leo considered Splinter for a moment. "So, April said that you know all about our plan now."

Splinter ran his hand down the length of his beard. "I do. It is a dangerous plan, formed in desperation."

Leo stared at the ground. "I am desperate, Sensei. You just—it was like you left us. I had to do something. You chose me as the leader, so I led."

"You did. I have never been prouder of you."

Leo jerked his head up. "What? It's a terrible plan! I went behind your back!"

"Only because I had turned my back to you. I am sorry, my son. The plan is dangerous and desperate, but it is the only option. You had the wisdom to see it, to fight against despair."

"Master Splinter—for this plan to work, I'm going to need you at some point. Even with Aunt Mei helping me—she's not enough to replace all that Donnie did for our team. I can't do this without you."

Splinter bowed. "Of course, Leonardo."

Just like that. Was Splinter—following his orders?

Had he really become the leader of all of them?

"Sensei—"

"I knew that I made the right decision when I chose you as leader, Leonardo. But now I have peace in knowing that even when I am gone, you will hold this family together."

Gone? A selfish thought popped into Leonardo's head. Of course Splinter wanted Donatello back for the same reasons all of them did, but was it also because Donnie could make the retro-mutagen? So that he could leave the sewers, leaving Leonardo behind to lead his brothers alone? Leo chastised himself internally for the thought.

"I sense that something else is troubling you," Splinter said. "Tell me."

Leo couldn't hold it in anymore. "Sensei, when—if—we get Donnie back, are you going to ask him to un-mutate you?"

Splinter drew a deep breath. "It is unwise to think so far down the line."

"But—if you became human again, Sensei—you wouldn't leave us, would you?"

Splinter put his hands on Leo's shoulders. "Human, mutant, it matters not. I will not leave my sons."

Relief and shock flooded Leo. "But—you could have a chance at a life, a real life! Not being an outcast!"

Splinter pulled Leo into an embrace. "The only life I want is here, with my family. I will be an outcast from the rest of the world regardless. You four are my life."

Leo squeezed his eyes shut to keep tears from escaping. "I thought—when Donnie made the retro-mutagen, I thought that—"

"That I would abandon my flesh and blood?" Splinter asked, releasing Leo from the embrace.

"But Sensei, we aren't your flesh and blood. We're just—"

"My sons. My offspring. I do not care where you came from or how you came to be my sons. It does not change how I feel about you."

Leo mentally slapped himself for his fears. He had foolishly projected his own insecurities onto his sensei. "Hai, Sensei." They hugged again briefly. It was strange. It was not as though Splinter never hugged them when they were younger, but he had stopped once they reached adolescence. Leo never really missed it, but in this moment, during this time, it was exactly what he needed.

"We need to get started," Leo said, blinking the moisture from his eyes. "I'll let you know when we need you. For now, we need to get in touch with Karai so that Aunt Mei can talk to her. Aunt Mei is ready to call Casey as soon as he's done with school, and it's just about that time now."

Splinter nodded. "Of course."

They parted with a formal bow, and Leo went to find Aunt Mei. She was sitting in the lab with Donnie perched on her shoulder, fiddling around with the computer. Mikey hovered behind her.

"Why don't you just call her with your phone, Auntie M?" Mikey asked. "You're with an outside network."

"I'm not risking it," Aunt Mei said. "If Shredder finds Karai's burner phone and my number is on it, he could back trace it."

"Couldn't he do that with Casey's phone, though?" Leo asked, walking over. Even if Casey had betrayed them in the past, they still needed to protect him from the Foot.

"Yes," Mei said. "And we can help protect Casey if that happens. But Casey has never been in the lair and I have. It could give away our position."

Curiously, Leo looked at the computer screen. A complex molecular diagram filled it. "What are you doing, Aunt Mei?"

Aunt Mei sighed. "Just trying to make sense of this mutagen molecule. It's enormous. The retro-mutagen molecule is at least half this size. I don't know much about chemistry, but I'm wondering if we could synthesize a retro-retro-mutagen based on the retro-mutagen molecule."

"Dude, if you say the word 'mutagen' enough times, it starts to sound really weird. Mutagen. Mutagen. Muu—taa—gehh—"

"Can it, Mikey!" Leo shouted. He shook his head. "So, do you mean we might not need the Kraang at all? That you can figure this out?"

"I can run the same program that Donatello ran on the original mutagen molecule, but run it on the retro-mutagen instead."

"Muu—taa—gehh—nnnnn..." Mikey muttered under his breath.

"Michelangelo!" Aunt Mei snapped. She drew a deep breath. "I don't know what to do with the information once I have it, though. I've got Kirby combing over all of the other diagrams and notes that Donatello made, so maybe between the two of us we can figure this out."

Leo suddenly realized April's absence. "Where are Kirby and April?"

"They went topside. They said they were going to get lunch and then hit the library so that they can study up on chemistry."

Leo allowed himself a brief chuckle. "Donnie would have killed to have access to a library." He patted Donnie on the head; in response, Donnie nipped his finger. "Ow! Geez, Donnie!"

"Dude," Mikey said. "No one likes to be patted on the head." He proceeded to pat Leo's head.

Leo slapped Mikey's hand away. "Thanks for the demonstration," he snapped. "Hey, we need to get in touch with Karai. You'd better call Casey. I'll go get Raph—where is he, anyway?"

"His room, I think," Mikey said. "He's been in there for most of the day."

"Okay," Leo said. "I'll be right back." As he headed for Raph's room, he felt a vague sense of foreboding. Raph had been known to spend hours in his room before, but Leo's intuition was on edge.

He knocked on the door firmly. "Raph? Gear up. We're getting ready to go."

There was no answer. Leo knocked again. Maybe Raph wasn't in his room. He twisted the doorknob to check—it was unlocked, which probably meant that Raph was elsewhere. He always locked himself in. Leo opened the door to check, just in case.

He was surprised to see Raph lying on the bed. Raph was just staring at the ceiling, holding his face mask in one hand.

"Raphael?"

Raph closed his eyes. "Who are we kidding, Leo? We can't pull this off without Donatello."

"We can do this."

"I mean—I never stopped to think just how much he did for us. When we were fighting off the Foot last night—Donnie's always got my six covered and he just wasn't there. Fighting without him was like—missing an arm." Tears leaked from the corners of his closed eyes.

Leo leaned up against the door frame; seeing Raph cry was very unsettling. Raph hadn't cried about Spike, or April. He hadn't really even cried about Donnie, though his eyes had started watering when Leo had lashed out at him. And judging by Raph's face, he had been in here crying for most of the afternoon.

Lead, Leo told himself. "I know what you mean. Even with Aunt Mei—and Casey's pretty handy in a pinch too—it was still like we were one short. But we can still do this, Raph. We're gonna do it for Donnie. And then you can rub his nose in the fact that you saved his shell."

Raph snorted. A weak grin spread across his face for a moment, but then it faded. "That's just it, Leo. I was always giving him crap. He deserved better. If we do get him back—I'm going to treat him differently."

"I seem to recall you saying something similar when you thought I went down with the Technodrome," Leo said, with a touch of sarcasm.

"Come on, Leo. You already know I respect you."

Leo started. "News to me."

Raph shook his head. He sat up and tied his mask back on. "Well, let's do this. If Donnie's nose needs to be rubbed into something, I can't let him down."

Leo actually laughed. "Let's go. The others are waiting for us."

"All right, chief," Raph said, offering Leo a fist-bump.

The two of them headed back to the lab in silence.