The sisters have to live under false identities to be free of demons. Each sister remains unhappy and eventually decides to return to their Charmed lives. Paige, however, begins helping a young witch named Billie, who eventually discovers the sisters' magical secrets but agrees to keep them under wraps in exchange for witchcraft training.
After being presumed dead, the Halliwell sisters begin their demon-free existence with new identities: Phoebe is overwhelmed with visions of her future husband; Paige begins hearing her white lighter call, which draws her to a mysterious young witch; Piper attempts to deal with her financial situation, the club and her children. Meanwhile, a brash young demon decides that he wants the Halliwell manor as a trophy and plots to kill Victor to get to it.
Witches from magic school keep disappearing and reappearing seemingly insane. Billie notices the parallel and tells Paige that the kids are being driven mad by a fairytale: Alice in Wonderland
When Piper goes for a job interview with a corporate recruiter, she's shocked to learn that the background check of her assumed identity was that of a woman wanted for murder. Meanwhile, Phoebe has a premonition of Dex being in an earthquake.
Wyatt's school play brings out the competitive nature in Piper when her hand-sewn costume and parenting abilities are criticized by another Stepford-like mother who is actually a demon in disguise bent on kidnapping Wyatt in a plot to resurrect the Source. Meanwhile, Paige spies Dex with another woman, and despite Phoebe's objections, butts in.
Problems occur when Agent Murphy sees Billie use her powers to save an innocent. Billie also casts a spell to make Phoebe happy that causes complications for Phoebe and Dex.
Billie is determined to kill a particular demon but can't when confronted by memories of when her sister was kidnapped on Halloween. A reporter is constantly harassing the sisters and Paige attempts to throw him off by impersonating the ghost of a girl he knew. Piper and Leo are having problems.
Paige's father returns asking for her help with a demon who has a fetish for being behind the camera.
Searching through Homeland Security's cold case files, Billie discovers a belt that gives her superpowers. Paige meets Henry Mitchell, a handsome parole officer who becomes very important in her life.
Agent Murphy calls upon the sisters to help captured a demon who has been infected with a government created virus that causes magical beings to turn "Incredible Hulk." They have to find an antidote to the virus after Billie catches it.
Piper is visited by the Angel of Death who warns her to prepare for the upcoming death of Leo. Piper who refuses to give him up, casts a spell that turns all males of San Francisco look exactly like Leo to confuse the Angel. He is still able to find Leo, however, when Leo makes a mistake by letting him know that he can see him. Leo gets run over by a car. Piper summons an Elder and Avatar for answers since "everything happens for a reason" and is led to an Angel of Destiny. She claims that Leo's death was a cause for their motivation to prevail in a future battle. ...
Billie discovers she has a new power when she accidentally turns her parents into a couple of sophisticated assassins.
Paige and Henry are held hostage in a bank by a mortal who is controlled by demons.
Phoebe thinks about moving on with her lives when she signs a lease for an apartment. Paige decides to tell Henry she's a witch, and so elicits magical help to put him in a good mood. Plans are put on hold when a demon shrinks them and traps them in a replica doll house of the Manor.
On the eve of the Chinese New Year, Piper and Billie receive a sign they think will help them return Leo. Instead, they find and disrupt a demon battle with the guardians of the Chinese zodiac, and Piper is charged with protecting their mystical staff. Meanwhile, Phoebe throws a house-warming party, and Paige introduces Henry to the world of magic.
Billie and the Charmed Ones deal with Christy's return, while a surprise suitor appears to ask for Paige's hand in marriage. Meanwhile, Piper runs into an old flame, and demons plot to recapture Christy.
Piper organizes an engagement party for Paige and Henry, but the wedding is put in jeopardy when the couple begins to get cold feet. Phoebe notices a strange man following her, and soon discovers that he is Cupid. Meanwhile, a demon kidnaps Christy in order to lure The Charmed Ones into attacking the Triad and prevent them from taking over the Underworld.
Students from Leo's magic school are being hunted by demons, and they arrive at the manor asking for help. Piper is confident she can handle the situation, but the demons are more powerful then she anticipated. Meanwhile, Billie takes Christy to see their parents, with tragic results.
Coop realizes that he has fallen for Phoebe, but she yearns to be with a mortal. Piper tracks down killer demons.
Suspecting that Billie and Christy are the "Ultimate Power," Phoebe and Piper formulate a plan that will provide the answers they need to get Leo back. Meanwhile, Paige saves her new charge Mikelle from two Darklighters, and Christy traps the sisters in a dream state in order to prove to Billie that each of their "inner-truths" are driven by selfishness.
Convinced that The Charmed Ones are too self-involved, Billie and Christy team up to destroy their reputations in the magical community.Using her knowledge of the sisters, Billie uses her spells to make the girls seem like only care about themselves, and Christy amps each spell up to dangerous levels. Phoebe lusts after Coop, Paige can't hear her charges' calls for help, and Piper turns into a perfect 1950s housewife.
The Charmed Ones find themselves stuck in the Underworld attempting to restore the reputations that Billie and Christy tarnished. Piper sees Leo's ghost and he gives his approval for the sisters to team up with the demon Nomed. Billie, Christy and the Charmed Ones realize separately that they must conjure The Hollow, the most powerful force known to man, in order to defeat one another, leading to a devastating battle.
Piper, with the help of Coop, must travel back in time to change the events that lead to the deaths of her sisters.