The Charmed Ones have faked their own deaths, attended their own funerals, and must now accustom themselves to a life of normality. But not everyone is convinced they are dead, Paige is getting ring-tones from a new charge, and there's a new kick-ass witch on the block. [A curiously lack-lustre episode, which spends too much time agonising over the transition back to normality.]
The sisters are still trying to decide what to do with their new lives, and discovering freedom isn't all it's cracked up to be. Suspicious demons lay a trap to lure the Charmed Ones into the open. But the new witch, Billie, falls into it instead, so the sisters have to rescue her. She recognises them as the Charmed Ones, and bargains to keep their secret if they teach her everything about magic.
Piper is arrested for murder: she chose the wrong new identity. As her sisters attempt to find the real murderer, Piper discovers that she is an innocent. They must work to expose the true murderer. meanwhile, Phoebe has a premonition of an earthquake at Dex's art show.
Piper is feeling inadequate as Wyatt needs costumes for a school play. Billie and Leo discover the demons in Magic School have kidnapped Wyatt in order to resurrect the Source. The sisters have to rescue them, and re-vanquish the source.
Billie is observed using her powers to save an innocent. In contrition, she tries to help Phoebe and Dex's love life, which ends up with them married. Billie lays a guilt trip on the sisters, so they help her vanquish the demon. They decide they want their old lives back, so remove the cloaking spell. They get a new ally in Homeland Security to say they were in a witness protection scheme. Phoebe has to show Dex her new form.
The press are hounding the newly returned sisters, trying to discover what their (cover) story is. Billie is having difficulty vanquishing a demon, because she keeps having flashbacks to when her sister was kidnapped by one. Phoebe thinks she might be pregnant, but is having trouble talking to Dax. And Leo and Piper are having a marital spat. Paige demands help from the Elders, who tell her to show the Press how ordinary they are, so they'll get bored.
A demon has been trapping people in photographs to cause anguish to their families. When one trapped in 1953 is released after his father finally dies, he manages to escape. But he is a future white-lighter, in the charge of Paige's father Sam. Sam asks for help, but Paige is unforgiving, until Sam gets trapped by the demon. Paige "calls" to her father, releasing him, and all the other trapped souls. Meanwhile, a magical marriage counsellor causes Piper and Leo to swap bodies, to help them through their problems.
Billie puts on a magic belt that gives her superpowers, but it could lead her to destroying all men. The sisters must find out how to remove it before it drives Billie mad. But a demon is planning to use it to destroy her rival. Meanwhile, Paige must keep a new charge on the right side of his parole officer.
The sisters are asked by Agent Brodie to track down a demon, and are surprised by its strength, but it then dies. Billie, scouting Magic School for news of her kidnapped sister, is slightly wounded by another demon, who later also develops strange strength, then dies. The Elders explain that a virus is loose, infecting all magical creatures. Billie falls sick. The sisters discover this is all due to a failed government experiment, and deliberately infect themselves to track down "patient X", who is immune to the infection. Meanwhile Paige is left holding a baby, and Phoebe has the premonition of her daughter again.
Piper sees the Angel of Death; he says he has come for Leo. Pipe desperately tries to save Leo, even asking the Elders and Avatars why he has to die. Eventually, she summons the Angel of Fortune -- who says Leo must die so that the pain of his loss allows the sisters to fight a final tremendous battle. meanwhile, Billie is hunting the demon who took her sister. She finds a freezing demon who knows something, but before she can get the information out of him, the sisters appear, saying they have made a deal, and need his help to freeze Leo. Leo will be returned only if they win the battle. The demon helps, but is then vanquished by whoever wants to keep Billie from her sister.
Billie's parents come to stay, still in denial about her sister, abducted by a demon 15 years earlier. Billie accidentally transforms them into a pair of assassins. A demon plot to take over a powerful company exploits this, by hiring them to assassinate the company's current president. Billie discovers that her parents have been searching for her sister, but keeping the news from her. Piper saves the day by making a public confession, disguised as the real killer. Billie works out how to transform her parents back, and they are reconciled.
Billie is torturing a possession demon in the attic, to discover information about her sister, but Piper is not amused, as it's Wyatt's third birthday party. Meanwhile, Paige and Henry are accompanying Nick, one of Henry's parolees to try for a bank loan. When it is turned down, the guy snaps, and pulls a bank heist, with hostages. One of the customers fights back, but accidentally shoots Henry instead. Paige has nearly convinced Nick to give up, when he is taken over by the possession demon, who refuses, wanting to force Paige to expose herself by using magic to save Henry, under the eyes of the CCTV cameras. She heals him, instead. Meanwhile, back at the manor, Wyatt has spelled three of his toys to adult size, set on a quest to find Leo -- Phoebe has to convince the partygoers that they are hired entertainers.
Three demons shrink the sisters, and confine them in the doll house, taking their Power of Three to go and kill the Slave-demon who has their kind in thrall. The three the return to kill the sisters, but they trick them and get their powers back. Paige tells Henry she's a witch, and he doesn't freak.
A demon kills the current Chinese Zodiac staff bearer. Piper has to protect the staff until midnight, when it can be safely passed on. But it affects people around her, making them obsessive, allowing the demons to capture it. Billie learns how to use her powers better, and makes contact with her sister as a young girl, imprisoned by demons. She uses the new power to focus the energies of the staff, and vanquish the demons. Eventually, the staff is safely handed over to its next keeper. Billie returns to her sister...
A British witch arrives, claiming Paige as his destined bride. Billie tries to get her sister Christy to control her firestarting powers. Demons kidnap her, but Billie rescues her again, but this seems to be part of some more powerful demons' plans to put "the key" in place. Henry fights for Paige, then proposes to her.
Some demons warn the Charmed Ones about the Triad, which they though Cole had vanquished. They plan an attack, and manage to kill two of them -- not realising that the real danger is Christy. Cupid arives to mend Phoebe's heart. Henry and Paige marry.
Cupid breaks Phoebe's resistance to loving again. Some demons are torturing a witch who had tortrtured them in magic school. The remaining Triad stops them, and the witch sees Christy. So when he turns up at the Manor looking for help, Christy has to make herself scarce, by visiting her parents. The Triad demon has her parents killed to stop her being sucked back into her family. So she kills him -- which was her last test...
The sisters hunt the demon that killed Billie and Christy's parents, to discover who was controlling him. Chrissie wants to kill him for revenge, and Piper has to blast her to stop her doing so. Chrissie uses this to drive a wedge between Billie and the Charmed Ones. Paige is worrying about losing her identity because of marriage to Henry -- so Cupid puts her in Henry's body so they can work things out. Meanwhile, Cupid sets Phoebe up with a date, but is beginning to realise that he is in love with her. When the sisters finally find the demon, Christy and Billie follow them, and vanquish him. The sisters realise that Billie is the Ultimate Power, and Piper worries that they may have to destroy her.
Chrissie tries to persuade Billie that the Charmed ones have become selfish and too powerful, and that they must be stopped. Billie wants proof. So they put the sisters into a spelled sleep, where Billie can see what they truly desire. This puts Paige's new charge in grave danger, and she persuades Billie to let her waken, but she is then nearly killed by a Dark Lighter, and her new charge ends up rescuing her. Meanwhile, Billie sees Piper's desire to get Leo back, and Phoebe's for a daughter. She agrees with Christy that they need to be stopped.
Phoebe tels Cupid she loves him. Billie and Christy's childhood imaginary friend is plotting with the Triad to kill all the witches: the Charmes Ones, and Billie and Christy. Christy sets the whole of the good magic world against the Charmed Ones, by convincing them that the sisters are no longer bothered to protect them. They are cast into the underworld.
Each side makes their most powerful potion, but fail to kill the others. Some demons tell the Charmed Ones that the Triad is behind Christy and Billie. Each side opens the Hollow, and is possessed by its great power. With this, the three sisters destroy the Triad (again). Then they all fight, and the Manor is destroyed in a great explosion. (The possessing power then conveniently returns to its box.) Only Piper and Billie survive the blast. Leo returns.
A devastated Piper decides to go back to the past to change things. Billie likewise. Piper uses Cupids ring to do so -- but ends up batting backward and forward through time, meeting her past and future selves. Billie discovers she was being manipulated by the Triad, and joins the sisters, more time travelling ensues, and Billie is forced to kill Christy. Eventually everything is sorted out, and they all live Happily Ever After.