The sisters throw a party at the manor. Prue and Piper feel uncomfortable at having invited Leo, but he and Dan seem to be getting along. Phoebe has a midterm exam coming up and asks her sisters to keep the party quiet. Dan asks Leo about his Army experience, but Leo doesn't have a convenient lie to tell him. The guests soon leave. Phoebe, still studying, hears 1920s jazz music and comes downstairs, to find the manor in antique decor. An unseen force pushes her against a wall and begins removing her clothes. She falls down and shatters a lamp. Prue, Piper, Dan and Leo come back in and find her on the floor.
Phoebe explains what happened to her. She says it was like a "daydream" and more a "seduction" than an "attack". Prue and Piper are worried enough that they keep an eye on her through the night, and Prue walks her to her exam.
Leo, hanging glasses at P3, half-remembers one of his previous charges, who had a past life that seemed to be trying to warn her. He can't find out if this is happening to Phoebe due to his wings being (at least temporarily) clipped. Dan comes in and Leo leaves. Dan is worried about Leo, who seems to have no past.
Phoebe takes her exam and suffers another attack, this one more serious: the unseen force tries to strangle her and throws her to the floor. Later, the sisters and Leo consult the Book of Shadows about past lives. Piper finds a spell that will take its caster to a past life. Phoebe casts the spell and passes out.
Phoebe finds herself in the eyes of one of her past lives. Jazz music is playing, Model Ts and similar cars are driving down Prescott Street, and a speakeasy operates inside the manor. P. Russell (Past-Phoebe) wears an elegant red dress, a tiara and a necklace. Gordon Johnson (Past-Dan) is playing the piano, and looks apprehensively at Russell. A woman notices Russell is carrying several bags and asks her what's in them. Russell says they're herbs for her potions.
Russell goes to P. Baxter (Past-Piper), who apparently runs the speakeasy. Russell greets Baxter as her cousin, and asks her to have her husband, Gordon, play something different. Baxter pretends to humor Russell, but goes over to her husband at the piano and tells him to ignore her. Baxter picks up a compact from the piano. Meanwhile, Russell finds P. Bowen (Past-Prue) as a photographer, and also greets her as her cousin. Bowen says they need to talk, but Russell blows her off. Baxter comes over to Bowen, opens the compact and passes a sheet of paper to her. Russell confronts a little girl, Christina Larson, with a fortune teller and starting to cast a spell. She scolds Christina and smashes her favorite porcelain doll.
A man, Anton, finds Russell, pushes her against the wall outside a door and passionately kisses her. He gives her a potion that will triple her power. He suspects that her cousins are planning to kill her. She drinks it and shoots fire at a crate full of bottles. At that moment, present-Phoebe wakes up. She tells Prue and Piper that her past self was evil.
The sisters look for their family tree in the attic. Phoebe tells them that in their past lives, they were cousins living together in the manor. Leo says they looked the same because Phoebe's soul recognized their souls; people tend to travel in the same circles throughout time. Phoebe reports that she had no control over her actions. She wonders why she doesn't have the power to shoot fire; Leo replies that her past self must have abused it. She finds the camera that Phoebe Bowen used. Prue is surprised to discover that her past life was a photographer. Phoebe replies that she was a really good one, remembering the long line for portraits. She then finds the family tree and identifies herself as "P. Russell", on the basis of the day she died: 17 February 1924, exactly 76 years to today's date. Phoebe also notices that Russell died at the age of 24--the same age that Phoebe is now. Phoebe believes Russell is trying to warn her somehow about something that could kill her in this life.
The sisters and Leo find Christina in a retirement home. She is initially scared of Phoebe, remembering her as the one who broke her doll; apparently she recognized Phoebe's soul. The sisters ask her what she saw the day that Russell died. Christina says that Russell was an evil witch and was murdered. She remembers a "pretty necklace" ripped from the evil witch's neck and that she was strangled. They ask who strangled her, but Christina only cries for her doll.
Phoebe fears she'll be dead before midnight unless she can get back to the past. She casts the past-life spell again and now finds herself at the point she was before, blasting the crates. She is slightly apprehensive of killing her cousins. Anton says the necklace is an amulet and will protect Russell from the effects of witchcraft.
He is a powerful warlock who is after the powers of Bowen and Baxter. He glamours into past-Leo and goes to meet Baxter. He tries to kiss her, and then reveals his true face. He grabs her, but she gets away. Russell goes to Bowen and asks to talk--but instead, shoots fire at her. Bowen blows ice at the same time, crystallizing Russell's fire. As the patrons flee, Anton is choking Baxter when Gordon cracks him over the back with a cane. Anton sends Gordon flying into the fireplace. Baxter throws out her hands, and Anton goes into slow-motion before grabbing her neck again. Christina flees up the stairs and hides on the landing.
Bowen blows ice at Russell again, but it has no effect due to the amulet. Bowen blinds Russell with her flashbulb just as Russell is about to reply with fire, then knocks her down with a flying kick. The two grapple with each other. Meanwhile, Baxter knees Anton in his testicles causing him immense pain, the shock incapacitates and causes him to fall forward. As he falls on the floor in pain, attempting to guard his testicles, Baxter smashes the grandfather clock over him. She then grabs a drapery decoration and starts strangling Russell with it. Bowen rips off the amulet and throws it across the room. Bowen and Baxter tell Russell that they know Anton's a warlock, and they can't chance him finding her again--not even in the future. Bowen pulls out the piece of paper and reads a spell to end Russell's life at this point in every life to keep her from getting back with Anton--apparently this is why Phoebe Halliwell got the sense she was dying. Just then, present-Phoebe comes to. She is horrified that her sisters' past selves are the ones who killed her past self.
Prue and Piper try to comfort Phoebe. However, Phoebe is still devastated--and even more so that her past self was planning to kill her sisters' past selves. Prue tells Phoebe it wasn't really her. Phoebe says that in a sense, it was her; she's scared that she might actually be evil. She also reveals that her past self was good, but Anton seduced her into turning evil. After she tells them that Anton glamoured into past-Leo, Leo reveals that he was Baxter's boyfriend before she married Gordon. He'd known this all along; he'd seen all of his past lives when he became a Whitelighter, but didn't tell her so as not to influence her choice between him and Dan. This doesn't make Piper happy at all.
Phoebe knows for certain she'll be dead by midnight because of the curse Bowen and Baxter put on Russell. Apparently Bowen and Russell thought Anton and Russell were soulmates, and since Anton is immortal they couldn't chance them ever getting back together again in any lifetime. She thinks the amulet could protect her from the spell. Piper and Prue check the Book of Shadows while Leo and Phoebe go back to Christina's room. Christina says that the good cousins threw the amulet into the foyer. Phoebe proposes to write a spell to give her control over her actions in the past so she can hide the amulet and be able to find it in the present. Leo warns that the only way to do this is to switch life forces, leaving Russell in her body. He doesn't like the idea since it risks releasing a powerful evil witch in the present. Phoebe quickly writes a spell and casts it.
The switch happens just as Russell is croaking out a threat to kill her cousins. Suddenly, "Russell" kicks Bowen out of the way, and then throws Baxter over her shoulder. The good cousins wonder where "Russell" learned how to defend herself. "Russell" looks frantically for the amulet, but can't find it. Bowen is surprised that "Russell" isn't trying to fight them anymore, but Baxter thinks it may be a trap. In the present, "Christina" gets up from her wheelchair and produces the amulet. She reveals herself to be Anton in a glamour. Before Leo can react, Anton slugs him through the bathroom door, where he has tied up the real Christina. Anton awakens Russell, who is now in Phoebe's body. Anton then puts the amulet around Russell's neck, and the two passionately kiss each other.
In the past, the cousins are still trying to kill "Russell", who tries to tell them that she's from a future life. The cousins don't believe her. "Russell" tries to switch back, but present-Russell is wearing the amulet. Bowen blows ice at her again, but misses. In the present, Piper and Prue are comforting Christina over what has happened. Leo thinks that since Christina is the only surviving link to the events of 1924, Anton used Christina to get at the present sisters. They realize that they have to somehow get the amulet off Russell--but only long enough so Phoebe can switch back, since she has to be wearing the amulet to protect her from the curse. Prue suspects Anton and Russell are at the manor planning to kill them, so they head back there.
In the past, "Russell" tries to switch back again, with no luck. She runs into Anton and high-kicks him across the room. Just then, the good cousins sneak up on "Russell". Phoebe throws the decoration around her torso while Priscilla starts strangling her. In the present, Prue, Piper and Leo arrive at the manor to find Anton and Russell waiting for them. Prue tries to fling Anton through the door, but Russell is holding his hand, extending the amulet's protection to him as well. Russell shoots fire, but Piper freezes the fire and she and Prue duck behind the couch. In the past, "Russell," with difficulty, tries once again to switch back while being strangled. In the present, Russell shoots fire again, but Prue deflects it at Anton, sending him up in flames. Piper knocks out Russell and takes the amulet. The switch now succeeds, and Russell dies in the past. Phoebe comes to, gagging and near death. Prue puts the amulet back on Phoebe. The amulet glows, averting the curse.
Piper isn't sure how to handle that she and Leo were lovers in the past. Just then, Dan arrives. He thinks that Leo is not for real. He checked with his brother-in-law (Jenny's father) at State Department, who revealed the only Leo Wyatt recorded in the Army died during World War II. Piper knows the truth, but can't tell Dan.
Phoebe is writing a warning about Anton in the Book. She tells Prue that she's worried it won't do any good if any of her future selves turn out to be evil. Prue says that Anton probably knew Phoebe is good now--otherwise, he wouldn't have needed Russell. She also says that everyone has evil in them, but it's just as natural to be evil as it is to be good--it's how to know what good is.