After the tragic death of Mel and Maggie's mother, the sisters struggle with moving forward but face another huge shock when they learn they have an older sister, Macy. With the emotions of all three sisters running high, each of the girls suddenly exhibit impossible new abilities: Mel can freeze time, Maggie starts hearing others' thoughts and Macy has telekinetic powers. While trying to understand their new powers, Harry Greenwood, gathers the sisters and reveals they're actually powerful witches, as was their mother. He also lets them in on a little secret, he's not really a professor, he's their "Whitelighter", a witch's advisor and guide. The sisters must make the decision to accept their new destiny as The Charmed Ones... and their new duty to protect humankind from the demons that walk among us... one of whom killed their mother.
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.
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.
While waiting for The Elders to arrive, the sister's patience is growing thin as they keep a watchful eye on their new charge. Once one of The Elders, Charity, appears, she gives specific instructions on how to handle the situation. Mel does not agree with the solution and enlists Maggie and Macy's and even Harry's help, but it means going against The Elders. Meanwhile, Macy, Mel and Maggie are all starting to realize that juggling their two worlds is becoming more difficult.
Mel is worried about Niko's safety, so Mel and Harry come up with a plan to protect her, but Mel will need her sisters' help. Maggie notices that Macy is upset about her situation with Galvin, so she offers to do some recon with her, but they discover that things might not be exactly what they seem. Meanwhile, Maggie's sorority sister Lucy turns to her for some help, but Maggie struggles with telling her the truth because it could jeopardize her sorority future.
With Maggie trying to make up with Lucy, she realizes that there is a new Kappa member she isn't familiar with and enlists Mel's help to find out what is going on. Macy is concerned about what she saw on Galvin and invites herself to his birthday party to investigate. Meanwhile, Macy is told a cryptic message about her past that she decides to share with her sisters, but her sisters have a secret from her.
After some unusual seismic activity, Harry informs the sisters that Hilltowne is a portal to hell. With that said, the sisters must band together to fight off a shadowy demon that is trying to obtain a collection of powerful magical artifacts. Meanwhile, Macy is given an exciting opportunity at work which comes with unexpected complications. Lastly, Maggie has a conflict of conscience over her relationship with Parker.
While on the hunt for Jada, Mel scours The Book of Shadows as Harry and Charity cross reference them to find any clues that might lead them to this new demon. As if that isn't enough, they discover that there is a Changeling Demon on the loose that puts one of the sisters in danger. Elsewhere, Maggie signs up for a job helping to market a new dating app which could land her a summer internship. Macy decides to go outside her comfort zone after a little encouragement from Maggie. Meanwhile, Mel is given a task by The Elders that she was not expecting.
Mel turns to Harry for guidance after learning information about the magical world that leaves her questioning everything she knows. Galvin shows up to see Macy and she is determined to not let fate get in the way of their potential relationship. Meanwhile, Maggie tries to keep her mom's Christmas traditions going and is excited for Parker to be a part of it.
The sisters turn to The Elders for advice about Harry. Mel, fed up with The Elders rules, turns to Jada for help without telling her sisters. With a plan in place, they must face an unexpected threat which leads Maggie to find a strength she didn't know she had. Meanwhile, Galvin shares some shocking news with Macy that will change everything.
Macy is eager to share the information she has learned with her sisters, but is thrown by their reaction to the news. To cheer herself up, Maggie decides to try out for an a capella group, but something doesn't feel right about the group. Meanwhile, Mel runs into an unexpected person from her past.
With Macy on a quest to find answers, she goes against Harry's advice and summons up a Necromancer which puts her and Maggie in harm's way. Maggie attends a frat party at Lucy's encouragement, to help her get over Parker. Meanwhile, Mel helps Harry who is struggling with his regained memories.
With life seemingly back to normal, Parker tips off Maggie to a mysterious death on campus that might be of demonic nature. After the sisters consult with Harry, they try to trap the creature, but they soon realize that not everyone can avoid its powers. Meanwhile, Galvin remembers something from his grandma's stories that could help Macy overcome her dark side.
Macy is trying to cope with new her new demon situation by watching a lot of her favorite TV shows, but things take a weird and dangerous turn. Mel and Jada enlist Niko's help to learn who might be after Jada. Maggie and Parker decide it is time to take their relationship to the next level, which leads them to make an unusual discovery. Meanwhile, Mel's powers seem to be expanding with the guidance of Jada leaving her to question The Elders intentions.
Maggie shows Macy, Harry and Charity the strange room under Vera Manor but they quickly learn just how dangerous it is when Mel and Maggie switch bodies and powers. Macy turns to The Elders for guidance about how to overcome her inner demon, which in turn leads her to have an eye-opening experience. Meanwhile, Maggie learns the secrets that Mel has been keeping from her sisters.
Macy is not able to trust herself due to her memory lapses, so she asks Harry and Charity for help. Stronger than she thought she was, Macy starts to piece things together and is eager to share her vision with her sisters. Meanwhile, Mel and Maggie are worried about Macy and turn to an unexpected source for help.
When Niko reaches out to Mel for help, she unknowingly reveals a new demon. Maggie volunteers to infiltrate the "cult" to help thwart him, but when she goes missing Macy and Mel set out to find her before it's too late. Harry must face the consequences of the "gift" that The Elders have bestowed on him, leaving Mel, Macy and Maggie shocked and angry. Mel thinks that Fiona might be the key to helping Harry, which seems to cause trouble between her and Jada. Meanwhile, Parker is getting worse and Maggie has an idea on how to make him better.
When Harry mysteriously disappears, a substitute Whitelighter, Tessa, surprises the sisters. With Galvin's return imminent, Macy knows she must tell him her decision about her demon side. Niko is curious when she sees that the Sarcana has cleared out and calls Mel for clarity, but when Mel arrives she is alarmed at what she discovers. Meanwhile, Maggie is trying to figure out how she can pay for college and turns to Macy for guidance.
With Harry still missing, Mel, Macy and Maggie devise a plan that requires to ask for Tessa's help. Parker is close to conquering his demon side, but all doesn't go smoothly so he turns to Maggie for what he hopes will be comfort. Meanwhile, Niko is eager to help Mel, but in return asks Mel for help in learning about her past.
With the Elders feeling that their lives are still in danger, the sisters and Harry band together to try and stop the evil that is happening. Mel and Maggie become concerned when Macy starts to tap more easily into her demon side. Meanwhile, Niko and Mel seem to be in a good place until Mel messes it up.
Galvin discovers that something bizarre is happening with the patients that are being brought into the hospital. Maggie gets a clue about how to keep The Source from taking over. Meanwhile, both Macy and Galvin do something no one could have predicted.
Maggie, Mel and Harry grow wary of Macy's new-found power. Meanwhile, Macy keeps creating alternate realities, but they don't end up being the perfect versions she was hoping for. Meanwhile, Maggie and Mel still struggle with what will happen in their personal lives.