It begins with the three sisters discovering they are descendants of an ancient Wiccan bloodline. As they try to keep their powers in check, Phoebe cannot resist peeking into the future to check out an attractive man; and Piper falls for the ghost of a recently murdered man who needs her help.
On their first anniversary of becoming witches, the sisters face a demon called Abraxas. Then, Phoebe has a premonition of herself being burned to death; a painting in Prue's auction house harbours a sinister force; and the girls meet their match in an evil witch searching for her wand.
Piper and Leo return from the angelic dimension to find a way of keeping their relationship alive; Prue and Phoebe try to save a little girl and a fairy princess from evil trolls; and the witches are called on to go back in time to save a baby due to be born on Halloween.
While Piper and Phoebe mourn the death of Prue, the Source uncovers the identity of a woman who can restore the Power of Three and renew the sisters' strength as witches. Then, Piper is possessed by a member of a band of supernatural vigilantes; and Paige makes a mistake with a potion, causing her to switch bodies with Phoebe.
The sisters help a former mermaid who struck a deal with an evil sea hag; an evil witch tries to increase her power by trapping the girls in warped versions of classic fairy tales; and a teenager with strange powers transforms the sisters into comic-book heroes.
Phoebe and Paige discover Leo is being held captive on the island of Valhalla; Paige gets caught up in a sexual harassment case; and a demon taps into the witches' secret desires and makes them come true in an alternative reality.
Piper and Leo accidentally acquire the power of the gods of creation and destruction at a Hindu wedding; the sisters try to prevent the murder of Lady Godiva before she can travel back in time and complete her famous ride; and a spell misses its intended target and transforms the girls into bickering teenagers.
The final season begins with Phoebe seeing visions of her future husband and Paige being drawn to a mysterious witch. Then, a demon plans to draw the witches out of hiding; Piper discovers her newly assumed identity is that of a person wrongly accused of murder; and Leo's school play brings out Piper's competitive instincts.