Poltergeist: The Legacy - Season 1 - Eps 15: The Thirteenth Generation
During the 17th Century a suspected witch is 'tested' by being dunked in water, as she goes to her death she curses the next thirteen generations of the Witchfinders family. While guest lecturing at a Boston University Derek gets involved in a series of murders/deaths that seem to involve the same family and could be connected to the long rumoured curse.
About Poltergeist: The Legacy

Title: Poltergeist: The Legacy
First Air Date: 1996-04-21
Last Air Date: 1999-11-12
Status: Ended
Rating: 6.1/10 (from 33 votes)
Language: EN
Seasons: 4
Total Episodes: 88
Network: Showtime
Genres: Sci-Fi & Fantasy
Production Companies: Trilogy Entertainment Group
Synopsis
The adventures of the members of a secret society known as the Legacy and their efforts to protect humankind from occult dangers.
Cast

Derek de Lint
Derek Rayne, Ph.D.

Martin Cummins
Nick Boyle

Helen Shaver
Rachel Corrigan, MD

Robbi Chong
Alexandra Moreau

Kristin Lehman