Phoebe and Paige search for Leo after Paige accidentally causes a ""chipper"" Piper to have amnesia, but the sisters soon learn he is being held on the mythical Island of Valhalla. Unfortunately they have no idea that it's because of Chris and his mysterious plans. Meanwhile, Phoebe discovers she is now an empath, and the dangers of this newfound power.

The Charmed Ones are called upon by The Lady of the Lake to help protect Excalibur, the legendary Sword in the Stone. Meanwhile, numerous magical beings arrive at the manor to try their hand at pulling the sword from the stone, but it's Piper who finally pulls Excalibur out of the stone, causing a surprise figure to appear.

A powerful sorceress switches bodies with Phoebe, who ends up trapped in the Underworld. Meanwhile, Paige faces a big problem when her new charge refuses her help.