In this episode Scott get to know that Alison's father is the werewolf hunter, and he afraid him too much but stiles tell him that he didn't recognize him so he can calm.... during Lacrosse practice Scott loses his temper and shifted into his werewolf form... but stiles took him away.... later they both have doubt that Derek is a serial killer they get him arrested.... but they get to know that Derek is not killer but the dead body they found from his house backyard is of his sister.....