Valhalley of the Dolls (Part 1)

Even though Leo is gone, Piper is in a surprisingly good 'chipper' mood, leading Paige to suspect that Leo altered Piper's memory. However, Paige's spell to restore Piper's memory clashes with Leo's and causes total amnesia. When calling upon Leo for help, Phoebe and Paige discover that he is being held captive on the Island of Valhalla, a mythical place ruled by warrior-maidens. Phoebe also discovers she is an empath, where she can feel people's emotions, much to the worry of Chris. So, he was forced to take a potion to block Phoebe's newly emerged empath powers to block her from reading him.