The sisters must face Hecate, a powerful demon goddess, who is preying upon a woman, her son & his fiancee, and attempting to conceive a full demon child.

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.

The sisters' mother warns them about a demon from the underworld who comes around every 1300 years on Friday the 13th to literally scare witches to death and feed on their fear. Meanwhile, Phoebe has misgivings about her expected duties at her new job and Piper is frustrated by her superstition about relationships started on Friday the 13th.