Cole drives Phoebe and Piper with the pedal to the metal in the SUV. Piper insists on pursuing and vanquishing a demon, but Phoebe would rather be teaching Paige about witchcraft. Piper, for her part, is still having trouble controlling her blasting power. They find their quarry, and Piper blows him up. His remains splatter the SUV.
Paige is distracted at work, reading a book about witchcraft. She is worried about a case. The mail boy, Billy, arrives and a coworker, a lawyer named Donnie, makes fun of his acne and Paige's breasts. Paige mutters "nice rug" and Donnie's toupee orbs to her hand, much to the laughter of the rest of the office.
Piper is crossing off the demons they've vanquished in the Book of Shadows. Cole is very worried about Piper risking her life to go after every demon she can find. He wants to lay low due to the bounty hunters on his tail, but cares too much about Phoebe to risk losing Piper. Phoebe is just as concerned because since Prue's death they've all but abandoned their old approach to vanquishing demons. Just then, Paige arrives. She's having trouble adjusting to her role as a witch. Piper leaves Phoebe to explain things, and goes to her room to scry for demons. Phoebe wants to stay and talk with Paige, but needs to go talk to Cole. Paige flips through the Book and starts marking it with Post-it notes.
Phoebe and Cole call for Leo, worried about Piper. Phoebe talks with Leo. Among other things, she's concerned that Piper is blowing Paige off. Phoebe is still adjusting to the fact she's the middle sister now; she looks at Piper and Paige and remembers the times Piper had to play mediator between her and Prue. Leo agrees to try to settle Piper down.
Paige runs out of Post-it notes and decides to take the Book with her. She heaves the Book out the attic window and abruptly leaves to return to work.
Leo tries to calm Piper down and begs her to tell him what bothers her. Piper says that it hurts to talk about how she feels about losing Prue. Leo thinks Piper is blaming him for not being able to bring Prue back, but Piper says it isn't his fault, it's evil's fault. Leo thinks Piper is going after demons to avoid facing her grief. Just then, Piper's scrying crystal lands; she heads out to find the demon.
Paige tries to copy the Book of Shadows on the office copier, but the copies come up blank. Donnie makes snide comments to Paige and Billy. Billy tells Paige that he's been deliberately losing Donnie's mail to pay him back for his taunting. Paige gives up on copying the Book. She casts a spell and Billy's acne clears. Paige is thrilled to have done some magic.
Piper charges off to do battle with the demon. Phoebe tells her not to expect any help from her or Cole. They spot smoke coming from a shed. Piper tries to blow the door open, but her powers are still unreliable; she ends up freezing Cole. She tries again and this time manages to blow it open but knocks Cole against a car. A man runs out, pursued by three women wearing tribal-like dress and markings on their faces. They also have long, sharp talons. Piper tries to freeze them, but ends up blowing up a car instead. She tries again but while Cole freezes, the women don't. The strange women attack Piper and Phoebe. Piper manages to unfreeze Cole just before one breathes smoke into Piper's mouth. Cole blasts her with an energy ball and the other two disappear in puffs of smoke. Piper starts coughing.
Piper is determined to vanquish the women, despite Cole and Phoebe's attempts to calm her down. Cole mentions that Piper has little control over her powers. Phoebe isn't surprised, since their powers are tied to their emotions, and they're all still grieving over Prue. Cole explains that the women they encountered are Furies, demonic vigilantes that go after evildoers. They will pursue and kill a shoplifter as easily as they would a murderer and take great pleasure in doing so. Cole tells Phoebe that he's encountered Furies before and that they have the power to make evildoers hear the cries of all of their past victims. Phoebe tells him that Cole isn't the same Belthazor who killed so many people over the years.
Piper finds the Book of Shadows missing and suspects an evil being has it. Phoebe admits to leaving Paige alone with the Book and the two go off to confront her. Paige, meanwhile, goes on casting spells for her own gain, such as extending the deadline for the Adam O'Brien application, and that of her coworkers. Donnie propositions Paige and she casts a karma spell on him to give him a taste of his own medicine.
Phoebe and Piper arrive at Paige's job. Piper is still ranting about Paige taking the Book, but Phoebe thinks it was because they haven't explained all the obligations she now has as a Charmed One. They find Donnie being pursued by a dozen women and Paige with significantly enlarged breasts. Piper freezes Donnie and the other women so they can talk. Paige admits having taken the Book and, after some prodding by Phoebe, also admits having cast several spells. Piper and Phoebe tell her that when she cast the karma spell on Donnie, it backfired and made her a target of ogling as well. Phoebe tells Piper to get Leo and orb Donnie back to the manor while she and Paige figure out how to clean up the mess.
Phoebe and Paige drive home. Paige apologizes for causing stress, but Phoebe says that Piper hasn't been herself since Prue died. Paige has trouble switching gears because her breasts are so big, and Phoebe has to help. Phoebe finds the Furies in the Book, and discovers that when a Fury breathes smoke into a good witch, the smoke opens up a portal of hidden anger. Eventually, the anger will build up until it consumes the witch's humanity and turns her into a Fury.
At the manor, Piper is roughing up Donnie, despite Leo's efforts to calm her down. Piper finally loses patience and blasts Leo. Leo reconstitutes just as Piper goes back in on Donnie. Cole arrives and warns Leo that Piper's turning into a Fury. Leo looks down and discovers Piper's fingernails have become very long, black and claw-like, like Fury talons. Leo tries to get Piper to fight it. Piper puts her hand to Leo's head as if to caress him--and throws him over the couch. She slices Donnie with her talons and starts to breathe smoke into him. Cole distracts her by hitting her with a small energy ball just as Phoebe and Paige arrive. Piper smokes away.
Leo heals Donnie. He comes to and starts eying Paige's breasts, but Paige knocks him back out with a punch. Leo orbs Donnie back to the office. Phoebe casts a spell, and Paige's breasts return to their former size.
A mugger is attacking two women when one of the Furies slashes him. He turns to attack them, but is brought to his knees by the cries of his previous victims. One of the Furies blows smoke into him, and he goes up in flames. Just then, Piper smokes in and tells them she's been looking around for them.
Phoebe scries for Piper, but can't find her because she isn't really a witch anymore. Cole shimmers in; he tried to sense Piper, but ended up drawing the attention of bounty hunters. Paige then remembers when she cast the karma spell on Donnie, she substituted "dirtbag" for "demon." She figures that she could change a lost-witch spell to find a lost sister instead. Phoebe doesn't think it will work if she's already looking for a kill. Paige then suggests using Cole as bait. Phoebe does not like this idea; Cole killed hundreds of people in the last century as Belthazor and their cries could kill him. However, Cole is willing to face up to his crimes in order to get Piper back, and talks her into agreeing. [Phoebe and Paige cast the spell, using blood from Cole's finger. The Furies are dressing Piper for a hunt when Piper hears the call. She tells the other Furies she knows where to find evil.
Phoebe, Paige and Cole wait for Piper to return. Paige is trying to figure out a trigger for her orbing power. Cole scares her, and she briefly orbs; fear is a trigger. They then discuss how to turn Piper human again; they have to close the portal of unexpressed fury. Phoebe thinks Piper is hiding something, and thinks it may be anger at Prue. Just then, Cole hears the cries of his many victims and knows that the Furies are already focusing on him. One barges through the door and Phoebe kicks her down. Piper and the other Fury smoke in, and Phoebe kicks them as well. She then tries to comfort Cole, who is unconscious from the cries of his victims. The Furies come to and surround Phoebe and Cole, but Paige orbs a lamp and throws it at one of them. They turn on Paige, but Cole blasts the other two Furies with energy balls. Piper attacks Cole, but Phoebe tries to calm her down. Instead, Piper turns on Phoebe.
Paige leafs through the Book for a solution before Piper comes after her as well. Phoebe calls for Leo, who orbs Paige and Piper to Prue's grave. At Paige's encouragement, Piper snaps and beats on Prue's plaque, berating her for dying and leaving her alone and finally returning to normal as she breaks down in tears, while Leo moves to comfort her.
The next day, Piper admits she slept better than she has in awhile. Phoebe tells her Paige handled herself very well considering that it hasn't been that long since she came into her powers. Phoebe adds that last name aside, Paige is definitely a Halliwell. Piper then admits she hasn't been too welcoming to Paige, but wants to reach out more to her. Later, Piper surprises Paige at her job with a basket of muffins. During their conversation, Piper warns her about using magic for personal gain and stealing the Book of Shadows, but, considering her and Phoebe's relationships with Leo and Cole, agrees to let it slide. Paige reassures her that, while it will never be all right that Prue is dead, it will get better. When Paige's boss approaches and asks why Paige isn't working, Piper explains that the two are sisters, leaving Paige visibly pleased.