Valhalley of the Dolls (1)

With Leo's promotion to Elder leaving Piper in a surprisingly happy mood, Paige decides to cast a spell on her to see if she's really as good about the changes in their lives as she claims to be. However, the spell backfires and leaves Piper with amnesia. Needing Leo's help to reverse things, the sisters soon discover that he's being held captive by warrior maidens and they take it upon themselves to go save them. Phoebe gains the power of empathy.