Prue & Phoebe have their hands full when Piper is possessed by the spirit of an evil witch, on the day of her high school reunion.

When a shapeshifting warlock tricks Prue into a shot-gun wedding in order to steal the Book of Shadows, Phoebe and Piper are lured to the dark side and begin to enjoy their new evil powers.

Paige takes the Book of Shadows into her work to cast spells which help her co-workers. Meanwhile, Piper, who is filled with anger over the death of Prue and the recent actions of Paige, is possessed by a member of a supernatural band of vigilantes known as the Furies.

As Phoebe prepares for her wedding day, she is completely unaware that the Source has taken over Cole's body, a plot that will likely ruin the big event. Meanwhile, when the Seer tells the Source that if he can marry Phoebe in the ""dark way"", it will insure that their future son will be the most powerful, evil being ever.

Phoebe falls prey to Jeric, a demon in search of the perfect body to hold the spirit of Isis, his dead lover. To trap the spirit, Jeric mummifies Phoebe's body. Meanwhile, Cole tries to save Phoebe by making a deal with the demon.