When the Halliwell sisters are exposed as witches on nation-wide television, they form a pact with The Source to reverse time and undo the damage. However, in the process, one of the sisters makes the ultimate sacrifice, placing the Power of Three in mortal danger.

With Leo as her guide, Paige goes back in time to her teen years, in an attempt to resolve her feelings about the accident that killed her parents. Meanwhile, Piper must prevent ghosts, who have inhabited Phoebe's and Cole's bodies, from fulfilling their mission.