With the instruction of Harry, the sisters are put through witch lessons, so they are able to properly practice their magic. However, when Macy learns of a mysterious death in her lab from Galvin, she informs her sisters and together, they devise a plan to suss out the demon. Trying to speed the plan along, Mel uses her magic irresponsibly leaving Harry no choice but to constrain her, which creates tension between them. Meanwhile, Maggie continues to struggle at balancing her two worlds - her sorority one and her witch one - especially after she volunteers to throw a Halloween party at her house.
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.