Three sisters (Prue, Piper and Phoebe) reunite and unlock their powers to become the Charmed Ones, the most powerful witches to exist. Now they must vanquish evil and save innocents while living their lives as normal women in the real world. Life isn't so easy when you're Charmed. In Season 4, half-sister Paige took over for the dearly departed Prue, to once again form the Charmed Ones and fight evil and save innocents.