After getting a message from the spirit board to not trust Harry, the sisters are conflicted and ultimately concoct a plan to see if he is telling the truth. Desperate to believe the person warning them is trying to protect them, they end up going against their better judgement. Harry soon realizes that the sisters are up to no good and tries to help before it's too late. Meanwhile, this new sisterly unit is not fully unified, with Mel and Macy struggling with who's the real big sister and Maggie caught in the middle.
Three months after their mother is killed by an unknown demonic force, sisters Mel and Maggie discover that they have an older half-sister, Macy. The first time the sisters are under the same roof, they unexpectedly start exhibiting new magical abilities; the eldest Macy receives the power of telekinesis, middle sister Mel can freeze time, and the youngest Maggie can hear people's thoughts.
Soon after, Harry Greenwood gathers all three sisters together and reveals to them that they are witches, as was their mother. Marisol had bound her daughters' powers when they were born so they could live normal lives, and was in the process of unbinding those powers on the night she was murdered.
The sisters ultimately accept their new destiny as The Charmed Ones, the most powerful trio of witches who protect innocents and vanquish supernatural demons.