Ep 15. Disturbing Behavior

Max and Isabel have always been the dream siblings, but that may not be the case anymore as Isabel's behavior has been increasingly unsettling as of late. She's taken to hypnotizing her friends and even her own family. Max refuses to believe that Isabel could be doing such harm and that's when Michael steps in to investigate her behavior, convinced that she's been taken in by an enemy alien.

Michael's theory is quickly proven right as the investigation leads them to a room where Nasedo, the shape-shifting alien who impersonated their adopted father, has been hiding. Nasedo has been feeding Isabel a serum that's been altering her behavior. They quickly come up with a plan to destroy the serum and save Isabel before it's too late.

Meanwhile, Liz still struggles with her feelings for Max, but she's trying to move on after their breakup. Maria and Alex are doing their best to keep her distracted, but when Liz and Max are forced to work together on a biology project, feelings are rekindled, and a kiss might just be in the near future.

Also in this episode, we see Kyle starting to have suspicions about his father. Valenti's recent behavior has been strange, and it's become clear to Kyle that his father is hiding something. He teams up with Sheriff Hanson to investigate Valenti and find out what's going on.

The episode ends with a twist that will leave viewers on the edge of their seats and eager for the next installment of Roswell.