Mel and Maggie are learning to navigate life without their sister Macy - Mel distracts herself with new flings at magical hotspot, the Blue Camellia bar, while Maggie is taking on more than her share of demon hunting. Meanwhile, Harry is struggling, mourning his lost love, and Jordan has teamed up with Maggie while navigating his newfound magical powers. Across the country in Philadelphia, an unsuspecting young woman... is living her life... mechanic by day, muralist by night... when she's suddenly thrust into a new world, coming face to face with the women she's inexplicably seen in her dreams. Just as Mel, Maggie and Harry are uncovering information about this mysterious new person, Josefina goes missing on her way to a pixie-pledging ceremony, and Mel and Maggie must rely on their "new third" to help their cousin... and find out if she is indeed the other Charmed One that they were told was "out there somewhere".
As the new Charmed One comes to terms with her powers, she finds herself resistant to accepting her destiny. Mel becomes protective and insistent on everyone embracing the new Power of Three, while Maggie is apathetic and aloof. But the girls must find a way to accept each other when a new threat starts tracking them.
Mel suddenly finds herself haunted by memories of her mysterious breakup with Ruby, while Maggie's demon-hunting habit puts strain on her relationship with Jordan. Harry tries to train the newest Charmed One, but gets derailed when they all must focus on a formidable new nemesis who starts wreaking havoc throughout the magical world.
When Maggie's demon-hunting leads her down a dangerous path, Mel decides it's time for them to take a break - and books the sisters for a weekend getaway. Meanwhile the new Charmed One is left in charge of the Command Center for the first time... which doesn't go as well as anyone hopes.
As Mel works to regain control of her powers, a conspiracy theorist hobgoblin threatens the lives of everyone at the Blue Camellia. But when Maggie and Kaela step in to help save the present, they end up getting stuck... in the past.
When a mysterious package arrives on the doorstep of Vera Manor, Mel and Kaela must turn to Dev to try and stop the Tallyman's (guest star ) deadliest attack yet. Meanwhile, Maggie is forced to do court-ordered "anger management" with a very unorthodox therapist.
Mel, Maggie and Kaela must divide and conquer when they become aware of a new, formidable threat inspired by the Tallyman. Maggie and Harry team up to chase down a lead in a dangerous magical realm. Mel needs Jordan's help healing a "creature" with whom she has a deep emotional connection. And Kaela's budding flirtation with Dev must contend with a surprise visitor from her past.
When it becomes apparent that conspiracy group The Unseen has assembled a hit list of anyone who has helped The Charmed Ones... the girls and Harry must scramble to warn - and save - their nearest and dearest now that everyone they know is an instant target.
Maggie is surprised by someone important from her past and tries to keep the peace when they collide with her present. Mel, Kaela and Dev are on the trail of the Unseen, while Jordan and Harry seek assistance from a different powerful trio.
As Mel, Maggie and Kaela are navigating their love lives, The Unseen bring an epic battle to The Charmed Ones'. Roxie seeks Harry's assistance, but his mission uncovers something - and someone - unexpected.
While the Charmed Ones are still reeling from a shocking turn of events, The Unseen have infiltrated every corner of the magical realm and are on the precipice of their plans to destroy the Power of Three forever.
An alarming event triggers a drastic change in the magical universe. Only The Charmed Ones, along with Harry and Jordan, can save the world where humankind and magical beings co-exist... but they'll risk their lives in the process.
Mel, Maggie and Kaela, along with Harry and Jordan, have now discovered that the cabal of foes coalescing to bring down the Power of Three are actually working for an ancient evil that's been laying dormant since the dawn of magic. This powerful dark force, known as the Lost One - will be the ultimate test of the strength of the newly discovered sisterhood, forcing them to rekindle their connection... or face the destruction of magic itself.