Charmed - Season 4

While struggling with the grief of losing Prue, Piper and Phoebe mourn over the loss of the power of three. However, when Piper tries to contact Prue using the Book of Shadows, she and Phoebe discover that they have a half-sister named Paige. It doesn't take long for the Source to learn of Paige as well, and tries to kill her before restoring the Power of Three.

After the sisters vanquish Shax, The Source of All Evil decides to turn Paige evil instead of killing her. As a result, the Source possesses her boyfriend to see if he can lure her to the dark side. Upon learning of the Source's plan, Piper and Phoebe do their best to track Paige down and convince her to fulfill her destiny to become a Charmed One. As this is occurring, Paige is discovering what her powers can do. Inspector Cortez suspects Piper and Phoebe are behind the deaths of Prue and Dr. Griffiths.

Still angered over Prue's death, Piper goes on a demon vanquishing rampage, ultimately putting Phoebe, Cole, and herself at risk. As they fight the demons called The Furies, Piper accidentally inhales some smoke that was released by the demons, resulting in her anger magnifying and becoming a Fury herself. It is only after going to Prue's grave is she able to let go of her anger. Meanwhile, Paige steals the Book of Shadows and uses it for her own personal gain at work after she and some co-workers get harassed by a boss.

While busy studying the Book of Shadows, Paige shows a large amount of jealously in how adept Phoebe is while performing her martial arts. As a result, when Paige mixes a potion, she accidentally swaps bodies with Phoebe, and while they try to hide the mix-up from Piper, they have a hard time doing so when the sisters have to go help a Zen Master save her kidnapped father from Limbo.

Paige starts having a bad feeling about a nearby house but is less than happy when Piper and Phoebe are hesitant to go investigate it. Later, with Leo's help, Paige is able to get Phoebe to go investigate – where Phoebe ultimately gets kidnapped and shrunken into a figurine by a demon called Gammill. When he discovers that his latest victim is a Charmed One, Gammill sets his sights on kidnapping Piper and Paige. Meanwhile, Piper decides to hire a concert promoter for P3, and when he starts making drastic changes, things do go as she hoped.

When Paige has a fairytale stuck in her head, she decides to use her magic and a special spell to bring to life a Prince from a favorite fairy tale that occurred in a past life. Little does she realize is that an evil version of herself also comes out of the story in order to get to take the Prince back and change history. While the Charmed Ones try to keep the evil enchantress at bay, they also have deal with a Shocker Demon attacking the manor.

After being attacked by a chameleon sent to the manor by the Source, Piper is put into a coma, where she is forced to live in an alternate reality. Before the Source is able to tap into her brain in order to drain her of her power, Phoebe, Paige, Leo, and Cole go through some drastic measures to save Piper by breaking the Source's hold on her.

After pondering a marriage proposal from Cole, Phoebe is forced to face a blast from his demonic past when the widow of one of his past victims hunts him down, looking for vengeance. As a result, they're forced to face an old protégé of Belthazor's who likes to kill witches with the same athame Cole used to use. However, when Paige learns of this, she has an instant mistrust of Cole and tries to convince her sisters to vanquish him. Meanwhile, Paige helps Leo and Piper find out whether they're ready to have kids.

Piper, Phoebe, and Paige learn that a warlock is in the process of kidnapping and enslaving the muses inside a special ring in order to make the forces of evil more powerful. As a result, they have to find a way to save the remaining ones and rescue the others before the warlock's plan comes to fruition. Meanwhile, Cole starts to get frustrated that Phoebe has so far spurning his marriage proposal and is worried that without his demonic powers, he'll be unable to help keep her safe from the demon factions who plan on attacking the Charmed Ones.

Still feeling guilty about her adoptive parents' death, Paige gets some help from Leo and the ghosts to go back to the day of their car accident so can work through her feelings and discovers how she was able to live through the accident. Meanwhile, Phoebe and Cole get possessed by a pair of ghosts who look to finish a job from 50 years ago, and as a result, Piper has to find a way to keep the ghosts in succeeding in their mission.

Phoebe is selected to serve on the jury of a man on trial for murder. During the case, she has a premonition showing someone else committing the crime, despite the evidence against the defendant. While Leo, Piper and Paige rush to find the rightful killer and bring him to justice, Phoebe does her best to stall her fellow jurors from finding the man guilty. Meanwhile, Paige's friend Glen is in town and Paige invites him to stay at the manor. While there, he discovers the Book of Secrets and soon finds out Paige's magical powers.

While at work, Paige discovers that a 10 year-old boy in foster care has the ability to magically start fires. Upon learning that his foster parents are actually demons who are attempting to get him to use his powers for evil, she, Piper, and Phoebe try to convince him to use his powers for good. Meanwhile, Cole proposes to Phoebe now that they are no longer possessed by spirits. However, when she puts on Grams' engagement ring, she falls under its magical spell and turns into a 1950's housewife. Also, Cole goes to work with Paige at the social services office.

When the Seer discovers that the Source will be destroyed by the Charmed Ones, he breaks a centuries old agreement between good and evil when he steals the Hollow, an ancient vapor, which he uses to steal Piper and Paige's powers. As this transpires, Phoebe has to work with Cole, despite having a premonition where she sees him sacrificing himself to save her from a demon. Meanwhile, there's more to Phoebe's premonition than meets the eye.

After getting a case of cold feet about marrying Cole, Phoebe decides to cast a spell where she brings her future, cynical self and herself when she was an innocent child to the present in order to gain some guidance as to what she should do. Meanwhile, Cole gets possessed by the Source and eventually becomes unable to resist doing his bidding. An evil demon called Kurzon attempts to align with the Seer to become the next Source and is sent on a mission to destroy the Power of Three. At work, Paige gets promoted to a social worker. However, worried that what she did in order to be promoted could be seen as a personal gain, she attempts to make things right with her co-worker that was passed up for the job.

When the Seer has a vision that Cole and Phoebe's son will be the most powerful being to live, she informs the Source of this. As a result, Cole begins to sabotage Phoebe's plans of having a white wedding, so they can get married in a dark ceremony.

As Piper and Phoebe begin gushing about how great married life is, Paige starts to feel left out, resulting in her suspicions of Cole being a demon again starting to grow. Meanwhile, the Seer gives Cole a special tonic that cause Phoebe to get pregnant as soon as possible.

When a pair of brothers who served in World War 2 with Leo return and seek revenge on Leo for their deaths, he has no choice to do what they want before the brothers hurt everyone he loves. Cole begins to plot with the Seer and a new demonic assistant to find a way to get Phoebe to move out of the Manor and into their own place in order to break the Power of Three.

When Cole attempts to unite the underworld before his coronation as the Source, a group of exiled vampires take it upon themselves to kidnap Paige, in an attempt to turn her and as a result, her sisters, vampires so they can claim the evil underworld throne as their own with the help of the Charmed Ones. However, when Cole learns of their plans, he orders that all vampires be killed, and as a result, Paige's life hangs in the balance.

After Phoebe tells Piper and Paige that she's pregnant with Cole's child, they team up with a wizard in an attempt to stop the Source before he ascends to power. However, they are unaware that Cole is now the new Source and that once his coronation takes place, Phoebe will take her place as the new Queen of the Underworld.

Irritated over the fact that Cole has been ignoring her now that he's the Source, Phoebe destroys several of his demons over the course of a couple days. It is at this time when she has a premonition about an innocent that will soon perish at the hands of a demon, and as a result, she goes to the manor to warn Piper and Paige. When Cole discovers what she has done, Phoebe has to choose which side she has to fight for: good or evil.

After banishing Cole, Phoebe's baby begins having strong demonic powers while still in the womb. As a result, the baby starts signs of open hostility toward Paige and anyone else who speaks ill of his father. What happens next is that the Seer takes it upon herself to steal the demonic baby from Phoebe and ultimately gain its power as heir to the Source.

Following the defeat of the Source, Piper, Phoebe, and Paige are visited by the Angel of Destiny with a tempting reward: continue their lives as the Charmed Ones or relinquish their powers and live normal lives. Their decision however, is put on hold when the sisters discover that they're being investigated by the FBI because of their involvement with a large number of unsolved cases. Meanwhile, Cole is trying to reach out to Phoebe. Later, after the sisters make their decision, Piper and Leo get some miraculous news.