The Charmed Ones--or so it appears--come into the attic saying that Phoebe had felt an entire family being wiped out by a demon. They are somewhat more provocatively dressed than normal. "Phoebe" is worried about the family's death, and "Paige" vows to personally kill the demon. "Piper", initially, wants to get tea, but agrees they should consult the Book of Shadows. "Piper" tries to grab hold of the Book, but it slams shut and leaps away from her onto the floor. "Piper" lunges for the Book, but it slides away from her again. The "Charmed Ones" morph into three evil but beautiful sisters: Mabel, Mitzy and Margo Stillman. They plan to steal the identities and powers of the Charmed Ones. They teleport out with a perfume-like potion as the real Piper comes into the attic. She looks surprised to see the Book on the floor.
Piper is making final preparations for a band due to play at P3 that night, but asks Jack, the new bartender, to be there for the sound check; she wants to be home when Wyatt wakes up. Phoebe arrives and offers to take Piper to lunch. Suddenly, Phoebe's empathy power kicks in; she whispers to Piper that Jack was checking her out. Phoebe shoos him away. Just as Piper and Phoebe are heading out, Chris orbs in. He says he has a lead on who sent Leo to Valhalla. Piper asks Chris and Phoebe if they left the Book on the floor last night. Both deny it, but Chris remembers something similar happening in his past. He thinks someone might be after the Book, but Piper and Phoebe don't take it seriously.
Paige has a new job at a fruit packing plant. Two gremlins, whom only she can see, shove a stack of crates and nearly kill a co-worker, though Paige saves her just in time. It's the third accident in a month.
The Stillmans are staying in a house across the street; they murdered the family who lived there. Margo thinks she'll get Piper's powers, and wants to use Piper's freezing power to stop the aging process. However, Mabel tells Margo that she'll get Piper's identity while Margo will get Paige's. Margo decides to content herself with orbing off a blemish. Mabel pours a brown liquid into a bowl and casts a spell allowing her to look in on the manor; only Piper is there. She plans to cast an "identity theft spell" that will make the entire world think the Stillmans are actually the Halliwells. However, all three Halliwells have to be in the manor for it to work. Mitzy is excited about the prospect of being able to orb, but Margo reminds her that as the youngest sister, she'll get that power. Mitzy and Margo get in an argument. Just then, a vacuum cleaner salesman shows up. Mabel conjures an athame and kills him with it. She then convinces Mitzy and Margo to put aside their differences for the moment.
Piper is trying to feed Wyatt when Leo orbs in. He badly misses Wyatt, and says he's been secretly orbing into his room to be with him personally, though as an Elder he watches over him all the time. He orbs back out just as Paige comes in. She mentions the accident at the fruit-packing plant. Piper asks if Paige left the Book on the floor. Paige denies it, and heads up to the attic to find out how to vanquish the gremlins.
Jason is in town again and Phoebe's empathy is still too strong for her to be close to him, but she's beginning to find some control. They make plans for a date that night.
Phoebe comes to the manor, bringing the Charmed Ones together. The Stillman sisters cast the identity theft spell. Mabel assumes Piper's identity, Mitzy assumes Phoebe's and Margo assumes Paige's. They test the spell by calling for Chris, who orbs in. Mitzy and Margo try to hit on Chris. They give him the athame they used to kill the salesman and claim it came from the astral plane.
Mitzy submits an article written in eyeliner, and comes on to Jason right in the middle of the office. Piper finds out that she supposedly fired the band, and heads out to the club to straighten things out. Paige and Phoebe are trying to brew a vanquishing potion for the gremlins when they discover the Book won't let them touch it. They call Chris, but he doesn't respond. Suddenly, they both get calls on their cell phones -- Paige has supposedly organized a rally for better pay and shorter hours at the packing plant, while Phoebe has seemingly written an article supporting multiple sex partners and suggesting that alcohol cures depression. They both rush out, planning to meet back at the manor later.
Piper is unable to convince the bouncer that she's the real Piper. Just then, Mabel comes out with Jack after having sex in the back room with him. She spots Piper and hides, but Piper doesn't see her. Piper freezes the room to get around the bouncer and tries to talk to Jack, but he doesn't recognize her either.
Meanwhile, Paige shows at the plant to find Margo leading a strike. A security guard asks for Paige's ID, and Paige obliges. When the guard sees Margo's picture on what should be Paige's ID, he hustles Paige out the door.
The evil sisters come into the manor and find Chris. He seems to be suspicious--and just in case, Mabel conjures a knife to kill him. It turns out that he was merely perturbed at being sent on a wild goose chase about the athame, which was not from the astral plane. Mabel orders Mitzy and Margo to keep their hands off Chris.
All three of the Halliwells are forcibly thrown out of their jobs. As Phoebe is thrown out the door of The Bay Mirror, she looks up and sees an ad promoting her column--but her picture's been replaced with that of Mitzy.
The Halliwells orb back to the manor and find the blonde sisters leafing through the Book. Just as Piper is about to freeze them, the Stillmans cast the To Separate a Witch from Her Powers spell and steal the Halliwells' powers. Mabel tries to blast Piper, but blows up a vase instead. However, the force of the blast knocks Piper into the wall, severely injuring her leg. Phoebe knocks Mabel down with a flying kick, only to be kicked down herself by a levitating Mitzy. While Paige is tending to Piper, Margo rushes at her with a lamp. Margo swings it, but to the surprise of both, Paige orbs out of the way. Margo sees the Halliwells getting ready to orb out, and yells at Mabel to freeze them. However, Mabel can't figure out how, allowing the Halliwells to make good their escape.
The Stillmans head to the attic; they want to find a way to kill the Halliwells. Mitzy scries, but can't find the real Charmed Ones because they aren't witches anymore. Margo is still angry that she didn't get all of Paige's powers. The Stillmans find they have an entry in the Book; it describes them as common witches who aren't worth vanquishing. They scoff because they have the Book, the Charmed Ones' identities and their powers. Jason arrives to take Phoebe out; Mitzy heads out with him to keep up appearances.
The Halliwells flee to a trashy hotel they know about, and are forced to pay with cash because their IDs have been altered. Piper's leg is bleeding badly; Phoebe and Paige manage to staunch it with some alcohol and a bandage. Piper is worried about Wyatt, but Phoebe doesn't think they'll do anything evil as long as the real sisters are still alive. Phoebe thinks that the sisters could get help from some magical creatures. Paige remembers the gremlins; she can still see them because she still has her Whitelighter powers. Paige orbs to the fruit-packing plant and threatens the gremlins with the potion she made earlier. She sends them to fetch Chris.
Phoebe goes to the restaurant where she and Jason were to have dinner and finds him with Mitzy. Jason gives Mitzy a diamond necklace, who appreciates the necklace by "thanking" him under the table. The real Phoebe punches Mitzy, and plants a premonition of all of them being in the manor again.
Mabel comes into the bedroom with Jack. They start going horizontal, only to find Leo in the room, holding Wyatt. Mabel talks Leo into taking Wyatt off her hands for a while, and Leo and Wyatt orb away.
The real Halliwell sisters orb into the conservatory. Suddenly, all the doors close and the newly Charmed blonde sisters confront the Halliwells when Chris orbs in. The real Halliwells try to tell Chris what's going on, only to confuse him since he recognises the blonde sisters as the Charmed Ones. Paige tries to orb but Margo has cast a spell to keep Whitelighters from orbing. Mabel blasts and misses several times, allowing the sisters to escape. The Halliwells hide in the attic, where they find a chest full of old demons' weapons. They take positions: Piper shoots a crossbow bolt just as the fake sisters arrive after them. Mabel panics and freezes the room. Just as the Stillmans get ready to kill the Halliwells, Chris orbs in and kisses Mitzy, saying they slept together. This enrages Margo, and she and Mitzy start arguing over Chris. Mitzy is going nuts from her empathy power. Mabel is angry as well; she ordered her sisters to stay away from Chris. Mitzy and Margo turn on Mabel. They go back and forth arguing with each other. Suddenly, a chandelier falls from the ceiling, the triquetra on the Book separates and the evil sisters lose their powers. The room unfreezes. The Halliwells deck the Stillmans (with Phoebe taking the necklace before decking Mitzy). It turns out that Chris had figured out the Stillmans' scam, and had deliberately provoked them into fighting with each other so they'd lose their powers. Chris hands the Halliwells the Book--apparently when the Stillmans lost their powers, all of their spells were reversed as well. The Halliwells use the To Call a Witch's Power spell to take back their powers.
After cleaning up the mess at the manor, the Halliwells bind the Stillmans' powers and turn them over to Darryl, who throws them in jail for murder. It turns out the Stillmans are wanted in eight other states. Piper tells Leo that he's more than welcome to orb in and check on Wyatt when he wants to when she's not around. Paige sends the gremlins to the junkyard, while Phoebe and Jason make plans to talk over lunch.