Derek is a new Alpha and teaches Scott how to use his werewolf instincts and how to protect himself from the hunters. He is also recruiting Betas for his wolf pack.
Aiden: I kinda overheard... well I listened in on Stiles talkin' to Scott about how he thinks he was the one that wrote that message to kill Kira.
Derek: You think Stiles, skinny defenseless Stiles, is the Nogitsune, a powerful, dark spirit.
When I find it, I'm going to kill it.Derek