As Coop realizes that he has fallen in love with Phoebe, she throws him for a loop when she wants to peruse love with a mortal instead of with a magical being. Meanwhile, as Piper tracks down the demons who killed Billie and Christy's parents, she begins to suspect that the demons and the sisters are somehow connected to the Ultimate Power. Paige turns to Coop for help with some issues she has in regards to her marriage to Henry. Christy tries to convince Billie that the Charmed Ones are out to get her.