Derek drove them back to the Red.

"You sure, you're okay?" Derek asked once again when he parked the car. He had taken Isaac's pain but that would have done nothing for broken ribs or internal bleeding. Human didn't heal as easily as werewolves. Peter's claw marks on his own throat had been healed before he'd even been out of the apartment but humans were different.

"I know how broken ribs feel." Isaac assured him. "I didn't hit my head. He just smashed me into the wall."

Derek shook his head with a small laugh. "That's what I told Stiles last time. He informed me that there's no just about it."

Isaac gave him a look but he couldn't hide the smile tugging at his lips. "We're both just so damaged."

There was no arguing that.

They parted ways and Derek rode the elevator up to the penthouse. He needed to clean up, he could feel the blood flaking on his skin, and change into a suit. It was still a bit early for dinner so he hoped that he wouldn't run into Stiles. Since they hadn't planned a date, the floor it was tonight.

After his encounter with Peter, mingling was the last thing he wanted to do today but it was part of his job.

He stepped out of the elevator and instantly knew that Stiles was also here. In his office, if he pinpointed the heart-beat correctly. So maybe he could slip into the bathroom without Stiles seeing the blood.

He made it to his bedroom door.

"Derek?" Stiles came out of the office. "How did it go?" The last word trailed into nothingness when he had a closer look at Derek. "Shit, what did he do?"

There were fingers on his face and throat again but Stiles was gentle and didn't try to hurt him.

Derek had to swallow before he could answer.

"Asked him about Scott." He said, avoiding Stiles' eyes. "That was his answer. Isaac got it worse."

"He okay?" Stiles asked and just hugged Derek close.

"A little bruised but nothing serious." Derek answered, hoping that it was true. He had only Isaac's word for it.

In his arms Stiles shifted as if he'd made a decision.

"You should clean up." Stiles said but didn't let go of him for a little while longer. "Put on something comfy, we're staying in tonight."

"We don't have to …" Derek started to protest but it was half-hearted at best. Staying in the penthouse with Stiles, maybe watching a movie, was exactly what he needed.

"I'll call Isaac and tell him that we won't make it downstairs tonight." Stiles ignored his protest, phone already in hand and with his free hand he ushered Derek in the direction of the bathroom.

Derek took his time for a long shower, he wanted to wash off Peter's scent. He didn't dare to think about what it meant that he didn't want to smell like his alpha. He was seeing Peter for exact that reason, to bond with his alpha, to reconnect with his pack, but it felt all wrong.

Stiles had said comfy so after his shower Derek put on sweats, a worn in t-shirt and thick socks. When he joined Stiles in the living room, he found him in his Spiderman pajama so they really would stay in tonight.

"I called Isaac. He says he's fine but I told him to take tonight off. With stuff like this he's almost as stubborn as you." Stiles rolled his eyes, if at him or Isaac, Derek couldn't tell.

"I canceled our dinner and ordered pizza instead." Stiles informed him. "Is that okay?"

"Sure." Derek frowned at him, trying to read him. He was twitching more than usual, his heart was beating faster and he was reeking of anxiety.

"Stiles?" He stepped closer, not sure what to make out of the situation. "What's going on?"

Caught Stiles gave him a deer in the headlights look and then he let out a nervous laugh.

"Damn werewolf senses." He rubbed the back of his head and was looking everywhere but Derek.

Building up to tell him something, was Derek's best guess. And judging by his behavior it was something big, something personal. Immediately Derek's mind started to race. Had Isaac told him about how weak and pathetic he was? How he let Peter push him around like that? Neither Isaac nor Stiles were werewolves, they couldn't understand. Peter was his alpha.

But Peter had hurt Isaac. Did Stiles want to break off every contact with him? He was Derek's alpha, he needed him. Was Stiles about to dump him? Was he kicking him out?

"Derek, I …" Stiles started but stopped and shook his head as if that was the wrong approach. "Shit, how do people do this?"

"Stiles." Derek felt his heart breaking but he didn't let it show. He was good at that, hiding his feelings behind a mask, but it had been a long time since he'd felt the need to hide from Stiles. "I get it. Just tell me to leave." It might be selfish but he was not leaving until Stiles said it.

"What?" Stiles swirled around to fully face him. If he didn't knew better, he'd say that Stiles got totally blindsided by that thought.

"I'm not dumping you, you idiot." Stiles almost yelled at him. "I'm trying to propose to you here."

Derek blinked at him.

Then he blinked again.

"Great, now I broke him." Stiles let out a resigned sigh.

"You …" Derek tried to comprehend what Stiles was trying to tell him. "You're wearing Spiderman PJ's."

"You're lucky you don't get a Deadpool ring." Stiles muttered but produced a small box from somewhere. It looked like a box for a ring. Was he serious?

"Why?" Was all Derek managed to say. He didn't understand.

"Why?" Stiles repeated, calmer now. "Because I love you and I want to spend the rest of my life with you."

Derek listened to his heart-beat but it was strong and steady, Stiles meant what he was saying.

Stiles gestured towards the couch. Sitting was a good idea, Derek didn't really feel his legs any longer and he just staggered after Stiles and dropped ungracefully onto the couch next to him.

"Why now is the more complected question." Stiles said, his long fingers fiddling with the small box in his hand. Shouldn't he offer that to Derek now?

"Why now?" Derek prompted when Stiles failed to elaborate himself.

"To give you a better standing against Peter." Stiles said, eyes still on the box. "If we're official he can't just take you away from me. But that's not the only reason."

Derek doubted that Peter would care much about pack politics but he guessed that he could ask Kali for help. She dominated Vegas, the other packs were only tolerated and she could just kick them out if she felt like it. Trying to force a beta to leave or betray his mate was against werewolf tradition. It didn't matter that in the human world her girlfriend and Stiles were rivals, first and foremost Kali was an alpha and it would weaken her status if she ignored a plea for help in a justified case.

And they couldn't try to make him spy on Stiles any longer. Thinking about it, it had been too calm on that front lately. Derek still didn't know what Peter and Ennis had to do with each other but neither of them could force him to turn on Stiles if they were engaged.

Plus, other alphas might be more willing to accept him in their pack if he came in mated. Not that he was ready for that step. Yet.

"What are the other reasons?" Derek asked.

"Just let me explain." The way Stiles said it made Derek wonder if he wanted to hear the reason behind this. "Please?"

Derek gave him a nod but for a long moment Stiles didn't speak.

"I know that the whole werewolves mate for life thing is bullshit." He finally said. "But you're more committed than the average human couple. I'm guessing, it's because you're careful of who you bring into a pack."

"That's true." Derek said. He reached over and put his hand on top of Stiles' which were still fiddling with the box. "Stiles, what's going on?"

"Isaac asked me to dom him." The words came out in a rush. "One scene, just to try it out. But if he likes it and we work out together …"

"What."

"Nothing sexual." Stiles hurried to say. "But with his past. He has trust issues. I told him that I'd find somebody for him but he won't be able to trust anybody except for me."

That Derek could understand. It had been the same for him. And that was the problem.

"I know what you're thinking." Stiles continued, now desperately clinging to Derek's hand. "That's exactly how we started. And if we do this, you'll wonder if Isaac and I will fall in love at some point."

"So you propose to me to ease my mind?" Derek drew his hand back and stood. He needed some space between Stiles and himself. "Is this just a joke to you?"

"No." Stiles stood as well. "Please, listen to me." He gestured over his chest, indicating that Derek should search for the lie in his words. "I want to marry you because I want to marry you. I bought this ring before I even knew about Isaac. We know each other for only a few months. I didn't want to rush things. I didn't want to pressure you into saying yes."

As much as Derek wanted to detect a lie, he didn't find any indication for that. Stiles' heart-beat told him that he was telling the truth and even if his scent was layered with anxiety and something that was almost fear, it to supported his words.

"I wanted to wait but then Isaac came to me and …" Stiles stopped, searching for words.

"And you just want to help him." Derek let out a sigh. Ever since he'd seen Isaac's face when he'd been watching Lydia and Kira, Derek had felt the urge to help him as well. But this was nothing he could give his friend. But Stiles could.

"What if you're wrong and you and Isaac do fall in love?" Why was he even considering it?

The look Stiles gave him was so full of love, it broke Derek's heart.

"For one, Isaac is straight as a stick." Stiles slumped back into the couch and reluctantly Derek took the seat next to him. "You should have seen his relief when I enforced the no sex rule."

"And second?" Derek asked.

"Nobody can control their feelings." Stiles sighed. "But at this very moment, I'm so madly in love with you, you can't imagine. I want to grow old with you."

"I want the same." Derek admitted quietly. "I don't want to lose you."

"You won't." Stiles assured him. "We don't have to get married if you're not ready for that. And I won't do anything with Isaac if you say no. But whatever you decide, I won't leave. You're stuck with me until you dump me." He bumped his shoulder into Derek's and they shared a shy smile.

"As for Isaac." Stiles continued. "If we do anything, and that's still an if, we won't use the playroom. That's ours. We'll get a room at the Jungle for our session. You'll know when we go there and I won't shower afterwards so you'll have a chance to scent me. If I ever have sex with Isaac you'd know. But it won't happen." He locked eyes with Derek, meaning every word he was saying. "He's not interested in me and I'm not in him."

"I have to think about it." Derek admitted, too overwhelmed by the whole idea to form a coherent thought.

"Take your time." Stiles reached for him and Derek leaned into the touch. "And if you say no, we will accept it."

Derek brought their lips together for a tender kiss. Somehow it ended with them stretched out on the couch, Derek on top of Stiles.

"So?" Stiles asked into the skin of his neck

"So what?"

"What's your answer?" Stiles pushed at his chest to get some distance between them so they could look each other in the eye.

"You haven't even asked the question yet." Derek reminded him. And he'd lost track of the ring box.

"Derek Hale, will you marry me?"

"Yes."