Cole is attending a deposition and is hearing everyone whispering that he's a demon. He's feeling increasingly paranoid and hides in his office, only to find Phoebe in his chair. She presents him with the final divorce papers. She calls him evil (or so it seems to hear) and urges him not to fight it. He almost chokes her to death, but as it turns out it's not really Phoebe, but Cole's assistant and she fearfully leaves his office. A ghostly Barbas taunts Cole, telling him that he's evil.
Back at the manor, Paige is trying to master one of Prue's most difficult spells - the Animal Conjuring spell. She's sad because even though she quit her job to be a full-time witch she still can't fill Prue's shoes. As Leo tries to cheer her up, Cole arrives, believing he's being followed. He hurls an energy ball behind him and Leo barely dodges it. Cole knows something is messing with his mind and he may end up hurting somebody.
At P3, Phoebe is talking to a young man when Piper finds her. Piper leads her into a back room and Phoebe is not happy to find Cole and Paige there. Cole tells Phoebe of his problem. Barbas whispers to Phoebe that Cole could be trying to turn her evil again, and Phoebe refuses to help him. Barbas then whispers to Piper that maybe she ought to let Cole go, and to Paige that her sisters are always two against her one.
In the Underworld, Barbas is standing on the edge of a pit of lava. Another demon has taught him to project up to the mortal world and he plans to acquire powers and escape from the Underworld.
Paige goes to Cole's apartment but Cole, thinking she's a demon, attacks her. She convinces him of who she is. Paige has brought a power-stripping potion. Barbas whispers to him that he fears hurting Phoebe. Cole takes the potion and loses his powers -- to Barbas, who is now free of the Underworld and fully corporeal. Barbas blows Cole out a window. Leo is able to heal him, proving Cole is no longer evil.
Barbas has called a council of high-level demons. Phoebe projects an image of herself into the room and tricks Barbas into vanquishing several demons. Barbas, angry, shimmers into the manor. The sisters try to vanquish him with the spell they used for the Source, but it fails. Barbas bricks over the walls and windows of the manor. The sisters are trapped, Paige cannot orb out, Piper cannot blast the bricks, and Leo cannot get in.
Paige believes that she is trapped in the baby's room and that the walls are closing in on them. Piper is afraid of spiders. Phoebe sees her date from P3 claim to be evil and shimmer away. Shortly after, though, they overcome their respective fears. They are sure that Barbas will try again, and decide to give Cole back his powers.
Piper sees herself as a child with her father and Grams. In her vision, a demon attacks and Grams vanquishes him. Victor is not happy with constant demon attacks. It's the scene in which Victor left for good. Barbas whispers to Piper that she will never be happy.
Phoebe, preparing a potion with Paige, sees Barbas where Paige really is. Barbas claims to have killed Paige and Piper. Phoebe attacks "Barbas", stabs him with an athame and only then realizes that she has stabbed Paige.
Barbas continues to whisper to Piper and she has a cramp in her belly. She fears for her baby, but soon overcomes her fear. She comes upstairs and blasts Barbas. Phoebe believes she is evil, but Piper convinces her otherwise and Phoebe overcomes her fear. The bricks disappear. Piper calls for Leo and he heals Paige.
Barbas has the backing of the Underworld to become the new Source, but he does not care, for he wants revenge against the Charmed Ones.
Cole agrees that he must take back his powers. Barbas comes blasting in and the power transfer potion breaks. Barbas traps the sisters, but Paige orbs the spilled potion onto Barbas. Cole vanquishes Barbas with an energy ball, then fades out solemnly as the family backs away from him in fear as he is now evil again.
In the final scene, Paige is seen in the attic, finally mastering Prue's Animal Conjuring spell.