There was a key to Peter's apartment in Derek's loft. He probably thought it was fair for both of them to have access to each other's places, that it was easier than just breaking in. When Scott told Stiles that Derek wasn't an Alpha anymore, that Derek had done something to help Cora and he lost his status to do it, Stiles took the key and drove over.

Peter didn't flinch when he heard the door unlock, Stiles didn't see him move from his place on the couch, feet on the table, arms crossed, and eyes closed. Stiles kicked Peter's feet off of the table. "Get up."

"Stiles", Peter greeted smirking and putting his feet back on the table. "Had a fun drive over?"

"What are you doing?" Stiles asked. "You're not sorry at all, are you?"

Peter opened one eye. "Sorry for what?"

"You killed your niece and someone else took the blame for what you did. Derek lost his Alpha status and you did absolutely nothing to stop it."

The smirk disappeared. "Kate Argent might as well have done the deed herself."

"Yeah", Stiles said, nodding. "I get that. You want to know what I don't get? Why you didn't stop him. He could have died. You realize that, right?"

"I told him that it was a possibility. He continued with it anyway."

"You should have done a better job", Stiles said angrily. "You should have kept him away from Cora or done it yourself, or helped him to take on the pain. He was giving up on himself. You know that he was."

"He had enough hope if he was willing to heal Cora", Peter told him.

Stiles shook his head. "He was willing to die if it meant that Cora could have a chance. He was perfectly fine with Kali killing him or it not working and dying anyway if it meant that she could live. And you just let him? Isn't there a small part of you that still cares about Derek? Isn't there a small part of you that remembers him being born, and wanting to protect him?"

"That was a long time ago", Peter said evenly. "Things change." He shifted in his seat and closed his eyes again. "It's already been done."

"You're his family!" Stiles exclaimed. "You're supposed to be there to protect him no matter what. That's what he was doing for Cora."

Peter got up from the couch. "Well, he wouldn't have done that for me, would he? If the roles were reversed, if I had foolishly attacked the Alpha twins and nearly died?"

"He left you alone with Cora in the hospital so that she wouldn't be by herself. Derek trusted that you wouldn't try and kill her. It's not much, but it's something."

"Derek wouldn't have risked his life to save mine."

Stiles nodded. "I still would have been there. You're Derek's family. I still would have been there."

"You yelled at him", Peter brought up. "You said that he was sleeping with Kate? Before the fire?"

Stiles was silent for a moment. "Gerard, he bragged about it to me. He called it his crowning glory. It was his best executed plan. He was hoping that Allison would become a better weapon on his team. I brought it up to Derek, because I was furious at him. I wanted him to hit me."

"Why?"

Stiles threw up his hands. "Because that's what Derek does, okay? He pins me against a wall or hits my head against a steering wheel. Its his way of showing that the fight is still in him. He should have punched me, I was expecting him to throw a punch. He didn't, and I knew that he was giving up. I knew when Boyd died that he was off, especially since he disappeared for days. It was understandable. I just didn't think that he was giving up completely."

"He'll be okay, Stiles."

"Yeah?" Stiles let out a laugh. "Well, he shouldn't have to be okay. He shouldn't have to just keep getting up after being beaten. You're supposed to be there, no excuses, no added agendas."

Peter looked stunned, but what came out of his mouth next wasn't an agreement. "Nobody told you that they left, did they?"

"Who left?" Stiles asked

"Derek and Cora. They left town."

"Vacations are always good", Stiles told him. "Little rest and relaxation. He needs a tan, a long nap, and a new razor."

"They're probably not coming back."

"You're lying." Stiles crossed his arms. "They wouldn't leave us behind without a word."

"Derek told Scott. I'm surprised Scott didn't say anything to you."

"Derek wouldn't leave for good without saying something to me, okay? Or at least something to Isaac, and as far as I've been seeing, Isaac's all happiness and sunshine. No sulking."

"Isaac changed allegiances", Peter informed him.

"Well, I don't care", Stiles said defiantly. "Derek would have said something about leaving for good. So when he comes back, and he will, you're going to be there for him the way you're supposed to be, understand? Or I'll hit you with another molotov cocktail."

"Sure", Peter said, sitting back down on the couch. "Anything else?"

"Yeah", Stiles said, uncrossing his arms. "Get some lamps in here. You don't live in a network of caves, but it's pretty close."

Peter smirked before closing his eyes again and Stiles walked out of the apartment, asking himself why nobody bothered to say goodbye to him when they left.