The Charmed Ones are assumed to be dead, and return to a demon-less life with visages that are unaltered to their eyes, but look different to the rest of the outside world. Phoebe wants to know more about the handsome artist who attended their funeral, which they attended incognito. Meanwhile, Piper worries that the demons will realize they're still alive, while Paige decides to help mentor a brash young witch.
A young demon named Haas hopes to trap the Charmed Ones by using the story of Alice in Wonderland to hook young victims, but Billie’s attempts to stop him cause her to become one of his trapped victims.
Piper is arrested after her attempt at finding a job through a recruiter leads to the discovery of her new assumed identity, which is that of a wanted killer.
As Wyatt’s school play approaches, Piper gets into a competitive rivalry with Mandi, one of the other mothers and a model of bland suburban perfection.
When Billie saves an innocent’s life, she inadvertently threatens the anonymity of the Charmed Ones when Homeland Security Agent Murphy, who has been keeping tabs on the Halliwell case, witnesses her action. Billie also puts a spell over Phoebe and Dex which causes them to get married. Meanwhile, Piper and Paige try to get their P3 club back into the black, and Leo and the sisters finally end up reclaiming their real identities.
Billie is hit with a swarm of childhood memories as she readies to vanquish a demon, The Dogan. She decides to reveal her tragic past to the sisters after a spell created to relinquish her fears fails to do the trick.
Paige's effort to get back into social work is sidetracked when her father, also a Whitelighter, asks for her help. Paige and Sam learn that his recently-escaped charge, JD was a prisoner of a demon that captured people across time and kept them imprisoned in photos.
Agent Murphy gives the Charmed Ones their first job for Homeland Security, during which Billie and Phoebe stumble across a belt that can pit men and women against each other. A demon planning on balancing things out on the women's side decides to try and use Billie to further her cause. Meanwhile, Paige and her charge's parole officer find a mutual attraction developing between them, while Piper and Leo try to book an act for their club.
Agent Murphy seeks the help of the Charmed Ones when a vicious demon breaks free of government containment. The demon is spreading a virus that unleashes a Hulk-like rage in magical beings, which infects Billie.
Piper tries to save Leo when the Angel of Death comes around again looking to take him. Phoebe and Billie find themselves trying to outmaneuver a sadistic demonic bounty hunter while tracking Billie's sister, while Paige seeks Henry’s assistance in the search.
Billie begins to have new thoughts about her sister's kidnapping, and begins interviewing victims of similar ordeals in the magic world, but soon stumbles upon a human subject who is really a demon.
Henry tries to get his parolee, Nick, a bank loan, but when Nick is denied, his outrage prompts him to hold the bankful of people hostage. Paige and Billie must then figure out how to end the showdown without magic when a horde of reporters arrive at the scene. Meanwhile, Piper and Phoebe try to curtail Wyatt's magic when he manages to make his toys come alive during his birthday.
Phoebe takes a new apartment and tries to start anew, while Paige and Henry decide to share a place of their own. Piper continues to cope with the loss of Leo. When a demon makes a sudden appearance and shrinks the Charmed Ones to miniature size, it keeps them locked in a tiny version of the manor, in hopes of harnessing their power to topple a vicious demon race. Meanwhile, Billie's sister remains missing, despite Billie's exhaustive search.
Piper stumbles upon a message from Buddhist monk Lo Pan as she tries to find out about Leo. Lo Pan also tries to show Billie how to harness her abilities to be used in the search for her sister. Meanwhile, Paige gives Henry a taste of the magic world, while Phoebe's housewarming party spirals into chaos.
Henry's interest in getting to know Paige's magical environment creates some problems for the relationship, just as she finds herself receiving interest from an amorous magic man, Sir Simon Marks. Meanwhile, Piper's old flame, Greg, comes back into her life, prompting her to think about dating again after Leo's death, and Billie finally finds her sister, Christy, and tries to help her return to a normal life.
Piper tries to set up a party for Paige and Henry's engagement, but the happy couple soon begins to wonder about whether or not to get married after all. Phoebe finds herself being followed by a man she later learns is Cupid. Meanwhile, Christy is kidnapped by a demon hoping to force the Charmed Ones into helping them keep the underworld from coming under siege.
Paige and Henry head off on a honeymoon, at which time Cupid pops in to carry Phoebe through a journey of past loves in the hope that she will find a reason to pursue love again. Piper is saddled with the task of overseeing some of Leo’s former students when they flee the enslaved Magic School. Meanwhile, Billie and Christy are thrown for a loop when their parents come to see them.
Phoebe is forced to decide whether she wants to be with a mortal or a magic man, but while trying to help her with that decision, Coop discovers he's fallen for her. Paige adjusts to the hectic schedule of being both a Charmed One and a married woman. Meanwhile, Piper corrals and questions the demons responsible for the murder of Billie and Christy's parents.
Phoebe and Piper come to a realization about Billie and Christy's powers and try to determine how that knowledge can bring back Leo. Paige rescues her new charge from a pair of Darklighters. Meanwhile, Billie is torn between siding with The Charmed Ones or siding with Christy, who hopes to reveal a wicked side to the sisters by exposing them to a dream world prison.
Billie and Christy try to compensate for what they perceive to be a lack of focus on the part of the Charmed Ones by making themselves look competent and the sisters look incompetent. Their diabolical efforts ensure that the sisters end up becoming victims of their own spells, and all three are soon forced to run to the underworld where they can quietly lay low.
The Charmed Ones are forced to restore their good name after being trashed across the Underworld by Billie and Christy. When they end up seeing Leo's ghost, he offers the sisters his blessing to utilize the services of a demon.
Piper and Billie decide to split up and try to bring back their respective dead siblings, with Piper turning to Coop to help her undo the event that caused Phoebe and Paige's demise. First, however, she must give a tearful farewell to Leo.