Piper & Leo, with help from Coop's ring, must travel back in time to change the events that lead to the deaths of Piper's sisters. Meanwhile, Billie uses her power of Projection to do the same thing; many familiar faces gather to help Piper in her time of need.
Forced to hide from Billie and Christy, the Charmed Ones find themselves stuck in the Underworld. Meanwhile, Leo appears to Piper and offers demonic approval; Coop searches for Phoebe; Billie & Christy resort to summoning the Hollow to stop the Charmed Ones and the Charmed Ones do the same.
In an attempt to destroy the reputation of the Charmed Ones, Billie & Christy resort to trying to make the magical community see that the Halliwells only care about themselves. Meanwhile, Phoebe begins to lust after Coop; Paige cannot hear her charges' call for help; Piper becomes the perfect 1950s housewife.
Piper and Phoebe devise a plan to recover Leo. Meanwhile, Paige rescues her new charge from a Darklighter; Billie is forced to make an important decision.
Coop comes to the conclusion that he has fallen for Phoebe but she'd rather spend her life with a mortal. Meanwhile, Piper is on the hunt for killer demons; Paige finds it hard balancing life as a Charmed One with that of a married woman.
Piper organizes an engagement party for Paige and Henry, but the couple begin to get cold feet. Meanwhile, Phoebe discovers a strange man following her but soon learns he is actually Cupid; a demon kidnaps Christy in order to get to the Charmed Ones.
Paige learns the difficulties of dating a mortal when Henry becomes too involved in the magical world and is torn when another suitor arrives hoping to convince her to marry him so they can become the ultimate magical couple. Meanwhile, Billie finally finds her missing sister, Christy; Piper faces a romantic decision when she runs into an old flame and begins to wonder if she should move on with her life.
With the intention of helping his parolee get a loan, Henry, along with Paige, go to a bank but instead the parolee decides to take everyone at the bank hostage. Meanwhile, Phoebe and Piper have their hands full when, during his third birthday party, Wyatt turns three of his toys into real people.
When her parents come for a visit, Billie accidently transforms them into assassins and also manages to contact a demon who is posing as a human. Meanwhile, Piper attempts to continue her life without Leo; Paige tries to make a connection with Henry; Phoebe tries to find a way to have her own life.
Agent Murphy gives the sisters their first Homeland Security case - searching through cold case files, where Phoebe and Billie discover a belt that gives Billie superpowers. Meanwhile, Piper and Leo are on the hunt for a band to play at P3; and Paige meets a handsome man, who happens to be her new charge's parole officer.
Wanting to return to her old career as a social worker, Paige's plans get put on hold, when her Whitelighter father, Sam, returns asking for her help with his charge. Meanwhile, Piper and Leo go to see a magical marriage counselor who thinks the best therapy is for them to walk a mile in each others' shoes - literally.
Billie must deal with her painful childhood memories of her sister's kidnapping, before she can vanquish her latest demon target, The Dogan. Meanwhile, the press are bombarding the sisters, since the announcement of their teaming with Homeland Security, so Paige goes to the Elders for help.
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.
Three sisters (Prue, Piper and Phoebe) reunite and unlock their powers to become the Charmed Ones, the most powerful good witches of all time, whose prophesied destiny is to protect innocent lives from evil beings such as demons and warlocks. Each sister possesses unique magical powers that grow and evolve, while they attempt to maintain normal lives in modern day San Francisco.