Phoebe Halliwell (Alyssa Milano) returns from New York and moves back into the family's Halliwell Manor in San Francisco to live with her sisters Prue (Shannen Doherty) and Piper (Holly Marie Combs). When Phoebe discovers the family's Book of Shadows in the attic, she learns that she and her sisters are the most powerful witches ever known, destined to protect both innocents and the world at large from demons, warlocks, and other evil creatures. Phoebe, reasonably suspecting the book to be a novelty, reads its initial inscription—unaware that it also happens to be an incantation activating the sisters' supernatural powers once all three are reunited in their ancestral home. By the end of the first episode, each sister learns that she has a unique magical power that allows them to cast spells and brew potions.