first episode;
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 accidentally 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 kwa warrior-maidens. Phoebe also discovers she is an empath, where she can feel peoples emotions, much to the worry of Chris.The sight of Leo causes Piper's pain to come flooding back, prompting her to stay behind on the island while everyone else escapes. The Valkyries follow Paige and Phoebe across dimensions to San Francisco and wreak havoc on the city. Phoebe has to control her new power in order to convince Piper that she belongs with her sisters, not the Valkyries. Meanwhile, Paige takes a job as a dog walker and is amazed when one of her mbwa is transformed back into a man.
source;wikipedia
