Piper and Phoebe struggle to come to terms with their sister Prue's death
Piper and Phoebe race against time to locate their half-sister Paige, but the Source has two days during which devious, manipulative methods can be used to tempt her
Paige has trouble controlling her new magical abilities and misuses the Book of Shadows. Piper falls prey to a supernatural band of female vigilantes known as the Furies.
Paige accidentally switches bodies with Phoebe after making a mistake while mixing a magic potion. The sisters must vanquish an apprentice ninja who has killed his master.
Piper, Phoebe and Paige walk into a trap set by a demon who lives in a scary old house and manages to shrink them to the size of dolls. Can the five-inch-tall witches escape?
Paige accidentally summons a medieval knight to the modern world. The warrior believes that Paige is the love of his life, but he is influenced by an evil sorceress.
The Source sends Piper into a deep coma where she sees an alternative reality instead of the real world. Phoebe and Paige must wake their sister before she gives up her powers.
Cole proposes marriage to Phoebe, but is forced to face up to his demonic nature when he meets another demon. Piper and Leo consider whether to have a family of their own.
A warlock is abducting all the Muses he can find in an attempt to build an evil faction more powerful than The Source. Can the Halliwell sisters find a way to release them?
Paige takes a trip back in time to her teenage years, guided by Leo, in an attempt to resolve her feelings of guilt about the accident that killed her parents.
Phoebe does her jury service on a murder case and soon realises that the defendant is not guilty when she has a premonition about the real killer's identity
Paige brings home an orphaned boy who is a firestarter in order to protect him from demons who want to exploit his dangerous talent. Cole proposes to Phoebe again.
The Source breaks an ancient agreement between good and evil by stealing a vapour called The Hollow that immediately absorbs Piper and Paige's powers.
Beginning to experience doubts about marrying Cole, Phoebe casts a spell that brings two more versions of herself to the Manor to help her decide what to do
Phoebe prepares for her marriage, unaware that the Source now has total control over Cole, while the Seer plots to change their wedding ceremony into a dark ritual.
Paige begins to feel left out because she is living with two married couples. Her isolation is made worse by her conviction that Cole is following an evil path.
Two ghosts from Leo's past who have been searching for him for 60 years finally catch up with him and seek revenge for the harm that they believe he caused them
A vampire queen who aims to undermine Cole's power in the underworld attempts to transform Paige into one of her own and turns her against Piper and Phoebe
Phoebe informs her sisters that she is pregnant with Cole's child. Piper and Paige team up with a wizard to prevent the coronation of the new Source.
Phoebe comes to terms with her new role as Cole's queen of the underworld, but after having a premonition she can't resist trying to save an innocent man from danger.
The Seer is plotting to steal Phoebe's unborn child and raise it to become the next Source so that the throne of the underworld can never be passed on to another demon.
In the last episode of season four, the Angel of Destiny offers the Charmed Ones a chance to relinquish their powers and lead normal lives. Cole is trapped in another realm.