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.

The sisters must face and destroy the demon that was responsible for their mother's death 20 years ago. In the process, they uncover a chapter of their mother's life that they never knew about - one that disturbingly mirrors Piper's current relationship with Leo.

The sisters trace a mysterious Ice Cream Van who abducts children, but the evil may not be who they initially suspect. Meanwhile, the girls' dad Victor comes for a visit.