Charmed

 "The origin story of Prue, Piper, and Phoebe in Charmed is one of the most important plot points, helping the audience understand why the three sisters did not know they were witches until adulthood.

The three sisters were born around 1970–1975, into a long-standing witch family. However, their fate was changed by a dark pact: Patty Halliwell, their mother, was forced to make a deal with a warlock named Nicholas. Under the pact, Nicholas would be protected by magic, in exchange for Patty's daughters receiving powers — but when they reached adulthood, they would be under his control.

Knowing this danger, the girls' grandmother, Penny Halliwell (Grams), acted to protect them. She cast a sealing spell, stripping the sisters of their powers and erasing their memories of being witches. From then on, they grew up as normal people, unaware of their magical heritage.

It wasn't until they grew up and stumbled upon the Book of Shadows that their powers were unleashed again — opening up their journey to becoming the Mighty Three, but also resurrecting the old covenant, putting them in danger from the very first episode.

If you want, I can rewrite this in a Book of Shadows-like mystical narrative style to make it more Charmed."