Valhalley of the Dolls (1)

Paige suspects that Leo has erased Piper's memories of their relationship, but her attempted memory recovery spell accidentally causes Piper to lose all her other memories too. Phoebe and Paige go off to find Leo, but he is currently being held captive on Valhalla, an island controlled by amazon warrior women called Valkyries. Also, Phoebe becomes an Empath, and Paige is startled when she sees a dog turned back into a human.