They were sitting in Stiles' living room putting together a giant Lego village, after having gone through the McDonald's drive thru on the way home from their shopping trip. Actually, Stiles and Isaac were putting it together, while Derek mostly sat on the couch and supervised. Buying toys was one thing, but playing with them was another.

Isaac had calmed down fully by the time they'd strapped him into his new car seat, which was a relief. The guilt of almost losing him was still gnawing at Derek, but it was easing with every smile Stiles was able to eek out of Isaac. Nothing like that was ever going to happen again because Derek wasn't planning on letting Isaac out of his sight if they ever stepped foot outside the house. Even playing in the yard was going to be heavily supervised.

Scott texted Stiles earlier that Deaton hadn't found anything useful yet, but he wasn't going to stop working on it. And that he would be back later that night to stay over. Scott had spent the least amount of time with Isaac so far, but Derek was appreciative of what he was doing. Although he wasn't planning on saying that out loud. He still had an image to uphold after all this was over.

"I think this town needs a movie theater. All the best places do," Stiles said, scratching his chin as he looked over what they'd built so far.

"I like movies too," Isaac said quietly. Stiles looked up at Derek, raising his eyebrows in surprise. Isaac was letting more and more slip out into conversation as the day went on. Nothing huge, but better than them having to drag every little thing out of him.

"Oh yeah, what's your favorite?" Stiles asked, keeping his voice from getting too overly excited. Better than scaring the kid with intensity.

"One of my brother's friends let him borrow Ghostbusters and I got to watch it," Isaac said, glancing around as if he was worried someone would overhear. "He told me I was gonna get scared, but I didn't."

"That's because you're brave," Stiles commended, shooting him a proud smile. "I think I've got a copy of it, if you want to watch it later?"

"We can?"

"Sure. Nothing goes better with pizza than a good movie. Great choice." Derek could see Isaac perking up even more in response to Stiles' praise. How he was so good at this, he'd never understand. Stiles and Isaac didn't even like each other, but he was able to put all that aside when necessary. Derek hated to admit it, but that was an area he was definitely lacking. He didn't even like to show the people he actually liked that he liked them, even though the list was already very short. Derek stood up, needing to get out of the room before he started thinking of Stiles as someone who he could accept advice from.

"I'm gonna go get something to drink. Want anything, Pup?" Derek asked, freezing when the words he said finally registered.

"Pup?" Isaac questioned, looking up at him in confusion. Stiles was giving him the same look, although his was tinged in amusement.

"It's just a nickname," Derek shrugged, feeling extremely uncomfortable. The older generation of werewolves used to refer to the young ones as pups, as a term of endearment. He didn't know why that slipped out now. "I don't have to call you that, if you don't like it."

"No one's ever given me a nickname before," Isaac said, scrunching up his face like he was thinking hard about it. "Well, my brother calls me Twerp sometimes."

"I don't have any siblings, but I hear big brothers can be a bit of a pain," Stiles said seriously.

"It's not so bad. My dad calls me a little shit too, but I don't really like that one," Isaac said casually, picking up another block. "I guess Pup isn't so bad." Derek could see Stiles' smile wavering at that bit of information. How Isaac could say that as if it wasn't a big deal was unsettling. And it was making Derek sick to his stomach.

"I'll go grab you a juice," Derek mumbled, escaping into the kitchen before he lost control. His grasp on his emotions was slipping and he felt the urge to run and never look back. It was like every bad decision he'd made was being reflected back on him by Isaac. Every awful thing he'd done as an Alpha and in the time leading up to it.

Contrary to what he presented to people now, Derek was a pretty docile werewolf growing up. He rarely got into trouble and that was mostly typical teenage stuff. It was when tragedy seemed to start following him that he felt the need to harden his heart and push everyone away. And now he didn't know any other way to live. But that didn't mean he didn't still feel like absolute garbage.

He heard Stiles make an excuse to get up and leave Isaac in the living room alone. Derek wanted to protest, since that still felt too far for Isaac to be at this point, but his presence would do more harm than good at the moment. And scaring him again was the last thing he wanted to do.

"What happened?" Stiles asked, coming up to stand behind him. Derek was leaning against the counter, trying to keep his claws from ripping everything to pieces.

"I broke Isaac's arm," Derek muttered, clenching his jaw hard enough to crack his teeth.

"What? When? He looks fine," Stiles asked in confusion, looking back at the boy who was still happily playing.

"Not this Isaac. Before," Derek sighed.

"Okay, but isn't that just a thing you all do to each other? It seemed like for a while all you and Scott did was fight. And you literally murdered Peter, but he's never really mentioned it. Erica gave me a concussion too. Such a strange life we're all living, isn't it?" Stiles mused, tipping his head to the side in contemplation.

"I'm not talking about anything like that."

"Well, do you want to explain it to me?"

"It was during a training session, after I turned Boyd," Derek said, keeping his eyes locked on the cabinet in front of him. He couldn't stand the thought of looking at Stiles while he said this. "I was testing his speed and agility, to see if he could take me down."

"Sounds reasonable so far. Kind of like lacrosse, just without the pads and safety standards."

"He wasn't able to get me once. And it wasn't even surprising because he'd only been a werewolf for a few days, but I was frustrated. There was this thing out there killing people and hunters breathing down our necks and all I could think about was the fact that my pack was completely unprepared. That if something came for us, we'd lose," Derek explained, reliving the fear of those weeks. Of course he had to cover his true feelings with anger, but in reality he'd been terrified. After getting rid of Peter, he was supposed to have time to build his pack into what he wanted it to be. But instead, he was playing from behind and just trying to keep up and stay alive. "So when Isaac mouthed off, I reacted."

"Oh."

"What he said wasn't even that bad. Now that I think back on it, it was nothing. But at the time, it felt like none of them were taking things seriously. And that's no excuse, but I felt like I needed to make an example out of one of them," Derek said, letting his disgust in himself color his words. "And why not choose the one whose father had just been murdered in front of him? The one who truly had nowhere else to go? The one who'd just escaped one abusive home, only to fall right into another?"

"Derek, you-"

"I broke his arm," Derek ground out. "When I turned him, I told him that I was giving him a gift. Something that would mean he never had to accept what his father did to him. That he would be powerful. And the first chance I got, I just proved to him that I was a liar."

"You're not."

"Really?" Derek said incredulously, finally turning around to face Stiles. He didn't deserve to hide from the scrutiny any longer. He needed to face the scorn he'd rightfully earned. "Then where is my pack? If I'm not a complete failure as an Alpha, tell me why they all left me."

"Isaac didn't leave you," Stiles reminded him, gesturing back to the boy who thankfully was none the wiser about what was going on in the room next to him.

"He never left his dad either. And I'm no better than him. Sticking around and being hurt is all Isaac knows."

"You are nothing like Isaac's dad, so shut the hell up," Stiles said firmly, staring at him intently. "You think in all those years of abuse he ever bothered to feel guilty like this?"

"That doesn't change what I did."

"No, it doesn't. And what you did is terrible. But systematic abuse over a decade isn't the same as one shitty move."

"You can't excuse away what I did. The fact that I knew what Isaac had been through and did the same makes me worse," Derek argued.

"Okay, so you screwed up. No one is saying you didn't. But unlike Isaac's father, who abused him until the day he died without remorse, you're standing here feeling like shit. And not that fake remorse people show when they get caught doing something wrong."

"But that doesn't erase what I did." How many times was he going to have to say that to Stiles before it got through to him?

"It doesn't mean you can't make amends."

"How? How would Isaac ever be able to forgive me?"

"You start by going back in there and taking care of that little boy, for as long as he's stuck that way. I don't know the rules of this shit or if Isaac will ever remember what happened, but you give him the best life you can while you've got him. And once he does turn back into teenage Isaac, you apologize for what you did and actually talk to him about it. No more emotionally constipated Derek Hale."

"You say that as if it's so easy," Derek scoffed.

"It's not going to be easy. Being an asshole is easy. Change is hard, but it's worth it, right? Even if things don't end up perfect, the effort you put in could make the biggest difference of all," Stiles replied, walking over to the fridge and grabbing the juice that Derek went in for. Before he left the room, Stiles paused next to him, staring at him seriously. "Don't let past mistakes be the excuse you use to never try to be better. It's a disservice to Isaac and a disservice to you. I've seen you be a complete asshole, but I also saw you holding that little boy in the middle of Target. Be that guy. I kind of like that guy." Derek watched Stiles walk out of the room, not knowing what else to say.

What Stiles said did make sense, but it still felt impossible to get past the guilt now that he'd let it settle into his bones. His life was full of mistakes that he just ran away from, instead of dealing with it head on. But he couldn't do it this time. Both versions of Isaac were depending on him to get his act together. Maybe trying to be better for Isaac would also help Derek be better in general.