Witches can't run away from their legacy, at least not the Halliwell sisters -- Prue (Shannen Doherty), Piper (Holly Marie Combs) and Phoebe (Alyssa Milano).
The Seer foresees that the son of Phoebe and Cole will be very powerful, and The Source, who possessed Cole's body, must bring him to the evil side marrying Phoebe in the dark way, i.e., in a cemetery with a dark priest and drinking the bride's blood.
S4E14 44 min
