The episode begins with Willow babbling to Oz about how they are seniors and now allowed to go off school campus for lunch. Still, it takes Xander, Cordelia, and Oz to get her to walk to the grassy area where Buffy has set up a picnic basket. They proceed to chat about Martha Stewart, Scott Hope, and the meeting Buffy will attend with Principal Snyder later on.
That night, we are introduced to Kakistos and his colleague, Mr. Trick, as they drive up to the Happy Burger drive-through. Trick orders a medium diet soda, but gets hungry as Kakistos proceeds to talk about exactly what he'll do to the Slayer. To eat, Trick pulls the drive-through attendant through the window and into the car.
Meanwhile, Buffy has yet another dream involving Angel, this time at the Bronze. As they dance in front of their friends, Buffy's ring falls off her finger. Picking it up, Angel experiences a flashback to Buffy killing him . He clenches the ring in his fingers until blood comes out, and blood also starts to stain his white shirt, exactly where Buffy had impaled him. He tells her to go to hell, and his appearance changes to that of a zombie. Buffy wakes up, and her mother is asking her if she's ready to face the Principal.
Principal Snyder lays out three guidelines that she must follow to be accepted again, though it is useless. The school board has already admitted her back in, and this fact prompts Buffy to take the mature stance regarding her reinstatement, and Mrs. Summers to take a childish approach to express her delight.
Buffy and Willow go to the library, where Giles has asked them to meet him for help on research. He wants to perform a binding spell on Acathla to make sure that the demon cannot be resurrected again. Buffy has to rush out in order to take her English make-up exam. Willow tries to persuade Giles about the magic she's been doing.
At the Bronze, Willow and Oz are kissing when Buffy comes up with drinks. She reveals that she passed her English make-up, and is glad to be back in her own life. Just then, Buffy is approached by Scott. When asked to dance, however, she babbles through a few excuses and a thank-you. Scott interrupts, and tells her where he will be if she wants to dance later.
Cordelia and Xander approach, calling attention to two of the people on the dance floor, one of which is dressed and acting like he is from a much earlier decade, dancing with a young woman. Buffy speculates that he might be a vampire, and follows them out, though she is distracted for a few moments by Scott. The gang follows her out as well, and right when they are ready to turn back, they track sounds nearby. The vampire was just about ready to bite when the young woman tosses him back. When Buffy arrives, the girl introduces herself as Faith, before staking the vampire and walking away.
Inside, Faith is telling a story to the gang and tells the others that her Watcher went to England to attend a retreat. Cordelia figures out that Faith must have been called as a Slayer when Kendra was killed by Drusilla. Faith wants to hear a story from Buffy, but is quickly deviated when Xander asks for a story involving the alligators. When Buffy is asked what her toughest kill was, she flashes back to killing Angel, but says that they are all difficult. Oz asks about her position on werewolves. Faith doesn't have a problem with them, and apparently thinks that Giles has gone to England as well.
Giles confirms that a Watchers' retreat is going on in England, but he wasn't invited. Upon meeting Giles, Faith says that she should have requested a transfer. Buffy invites her to dinner, and then asks Willow for help studying. She is ignored, though, and sits in the library. She leaves later, though, when Giles begins asking her more questions about the details of Acathla's demise.
Willow and Xander are showing Faith all the places in the school where the supernatural things occurred when Faith turns to get water. Finished, she accidentally bumps into Scott and the two start talking. Buffy appears to see the two apparently flirting. Willow starts talking about how Faith and Scott might hit it off, and agrees with Faith that Buffy needs to find the fun. Buffy drags Faith away and the scene switches to Kakistos.
Mr. Trick is filling Kakistos in on what they can do there, before informing the vampire that there is already a Slayer there, a fact which indicates that they are not after Buffy, but Faith instead. Kakistos also draws attention to the scar over his right eye, saying that "she will pay for what she did to me". Mr. Trick agrees, before going to answer the door and dragging the pizza delivery man in to eat.
Mrs. Summers and Faith are talking at the dinner table, discussing Buffy. Mrs. Summers appears to think that Faith might be a better Slayer than Buffy, then leaves to get another drink for Faith. Buffy follows to talk, revealing that she doesn't want Faith to steal her life, like she seems to be doing. Mrs. Summers says that Faith could share the slaying, though, and that they could even ask Faith to take over. Buffy accidentally tells her mom that new Slayers only come when the old one dies, and her mother freaks. They finish talking, though, and both feel better.
When they're patrolling, though, Faith starts talking about Angel. The two start a verbal sparring match before vampires interrupt. Faith starts beating one into a pulp as two drag Buffy down, mentioning Kakistos as they do so. When Buffy yells at Faith, the latter merely says that she was doing her job and walks away.
Buffy tries talking to Giles, but it doesn't help. Giles begins mulling over what might be going on at the retreat before asking Buffy details to trace their lineage. Upon hearing Buffy try saying "Kakistos", he rushes off to the library to grab a book. When the fact that both the vampire and Faith appeared around the same time, they begin wondering if they are connected. They set out plans and separate.
On her way out, Buffy runs in to Scott, who tries to ask her out on a date. Buffy accepts, but runs when Scott hands her a ring exactly like the one Angel gave her. Giles comes up, and tells Buffy that Faith's watcher is dead. Buffy goes to see Faith, and begins talking about Kakistos, surprising Faith with the fact that the vampire is in town. Faith starts packing, but Buffy brings up her watcher and stops her at the door. They are interrupted by a knock on the door, and Kakistos is outside with the dead motel operator.
Faith and Buffy run, eventually ending up in the exact warehouse where Kakistos has been staying. Faith begins to fall apart, right before bringing attention to the fact that they were herded there. Buffy fights the rest of the vamps while Kakistos starts beating Faith. Buffy intervenes, and Mr. Trick takes the time to leave with one of the other vamps. Buffy stakes Kakistos, but he's so old that a mere tiny stake isn't enough to kill him. Luckily, Faith finally recovers and picks up a thick wooden pole that she had broken earlier, using it to quickly kill Kakistos.
Back in the library, Buffy finally tells the others that Angel was cured when she was forced to kill him. Giles says that it will help with the spell, and Willow apologizes. When Buffy leaves, Willow once again approaches Giles about the spell, only to be told that the spell doesn't exist, and he was merely trying to get Buffy to tell what had happened.
Buffy finally talks to Scott, and they make plans to go out later on. The scene changes to show Buffy returning to where she killed Angel and stopped Acathla, finally able to say good-bye and leave her Claddagh ring. Then, she leaves. However, the Claddagh ring starts to shake, and a bright white light appears. When it fades, we see that Angel, naked and shivering, is back from Hell...