Freaky Phoebe

After a spell is cast on Phoebe by a power-hungry sorceress, Imara, their souls switch bodies and Phoebe ends up a prisoner in the Underworld.  Armed with Phoebe's identity and power, Imara attempts to gain control of the Underworld by weakening Zankou, destroying his lieutenants and plotting to kill the Charmed Ones.  Phoebe escapes from prison in Imara's body, but Piper and Paige vanquish her, not realizing that it was Phoebe's soul inside.  Meanwhile, Paige is left in a quandary when Mitchell, her first charge as a Whitelighter, refuses her help and appears to have been lost to the dark side.