"He is a bad influence," he pointed out firmly. "I don't trust him, and you should not either." Peter had killed Laura, and while Derek needed him right now, he did not trust the older wolf in the least. Peter would be useful until there was a better option, and Derek was under no delusions, Peter would betray him and the whole pack first chance he got. That was going to be dangerous, and Derek did not want to see Isaac hurt again.
Derek was not entirely stupid, he knew when he was being mocked. He settled a hard gaze on Isaac, then simply nodded to drive the point home. Besides, the manhandling had been out of necessity, and the Alphas would do far worse if they ever got their hands on any of them. Derek cringed internally thinking that Erica, Boyd and Allison probably knew that all too well.
He watched Isaac grab the book uninvited, sitting in silence a moment as he attempted to decide if he wanted to be offended by it. In the end, Derek decided there was no real harm done and let Isaac have the book. "We'll be moving soon." That was all the information he planned to give his beta, so far as the pack house was concerned, but it was more of a heads up than Derek usually gave. He was, potentially, getting better at this communication thing. Baby steps.
Isaac's question prompted a dramatic eye roll from Derek, and he wished he had something to put down or close dramatically so he could better illustrate just how ridiculous he found that question. "Because she's not." Derek drew in a slow breath and attempted to remind himself that he was talking to a teenager who was likely hopped up on hormones more often than not. "She's been hurt by some hunters, she's here looking for those responsible. We're going to help her find them and, in return, she is going to help us." There, that summed it up nicely, Derek thought.