That '70s Episode
S01E17 - Airdate: 1999-04-07
Runtime: 60 min
After Prue, Piper, and Phoebe cross paths with a Warlock named Nicholas, they discover that he is intent on obtaining their powers by any means necessary. When they discover that he's immune to their powers thanks to an agreement with their mother, they cast a spell to go back in time to the day the deal was made, hoping to stop their mother from going through with it.
Episode details and rating from TVmaze.