Acting on Phoebe's premonitions, the sisters race to stop a mysterious killer from striking again. Meanwhile, Prue finds a truth spell and uses it to find out what Andy's reaction to her being a witch would be.

A powerful warlock shows up claiming that he made a pact with the sisters' mother in which he spared her life in exchange for the girls' powers. Fleeing him, the three sisters go back in time to the 1970s when their mother was still alive and they try to prevent the pact.

After Piper leaves on a business trip, it doesn't take long for some friction to appear between Prue and Phoebe. However, they set their differences aside when they run into a ghost of a serial killer who's looking for a revenge against people who sentenced him with a death penalty. Meanwhile, the many unsolved crime cases are finally starting to catch up with Andy when people from Internal Affairs take an interest in them.