Scott and Stiles are on the outs after Stiles' dad gets hurt, but when Derek insists that Scott avoid Allison, Scott turns to Stiles to help him master his anger with the help of a heart monitor. Meanwhile, Jackson is feeling the effects of having been scratched and approaches Allison claiming to want to get to know her and Scott better.

As Scott's second full moon approaches, he gives in to his animal urges and hurts Stiles, but Stiles gets a measure of revenge in locking him up. Meanwhile, Jackson continues to try and get closer to Allison. The Argents learn that Scott somehow knew Derek.