Buffy and Angel have a cuddle session at his place. Buffy wants to add a few mirrors and a drawer for her stuff; she accidentally opens up a curtain to reveal the sun. She wants to go to the prom with him.
Anya asks Xander to the prom. He sarcastically declines at first, but he agrees after realizing neither of them have dates.
Angel finds a notebook of Buffy's that says, "Buffy & Angel forever." Joyce unexpectedly visits Angel and begs him to break up with Buffy since she has a full life ahead of her.
Giles and Wesley's research discover that the Ascension will turn Mayor Wilkins into a demon, but they're not sure which demon. Giles gets mad at the Scoobies for their conversation about prom outfits.
A mysterious student has a demon caged.
Angel has a nightmare of Buffy and Angel getting married in a church. Once Buffy steps out into the sun, she burns in ash.
Later at night, Angel and Buffy go down into the sewers for a bit of patrolling; Buffy stakes a vampire. Angel breaks-up with Buffy because he wants her to experience her life filled with marriage, kids, intimacy, and more.
Angel reveals that he's going to leave town after the fight with Mayor Wilkins.
Willow and Buffy talk about the break-up; Willow bashes Angel to support Buffy. Buffy is heartbroken and collapses into her friend's arm.
The demon from the cage breaks out.
Xander ambushes Cordelia at the clothing store as she's looking at a dress. He discovers that Cordelia works there because she wants to save money for a dress. Cordelia's father got indicted by the IRS; she lost all her mother and can't attend any colleges.
The caged demon bursts through the window and attacks one of the customers in a tuxedo.
The Scoobies review the surveillance footage of the demon's attack. They see a kid using a mechanism to control the demon; the kid is Tucker Wells. Tucker made a threat online against the student body st the Prom. Buffy plans to stop the demon so that everyone can enjoy the Prom.
While on patrol, Buffy sees Angel buying a bag of blood from the meat plant.
Cordelia is surprised to find out that Xander paid for the rest of her Prom dress on layaway.
Buffy forces the others to go to the Prom. Wesley is blown away by Cordelia's dress. Willow and Oz go together to the Prom. Anya tells Xander vanquishing stories from her past career.
Buffy surprises Tucker in his basement; she discovers that he brainwashed the demon with old Prom horror movies. She also discovers that he trained three other demons who already left.
Buffy kills the three demons before they break into the Prom. The Prom is being held in the gymnasium of Sunnydale High. She changes and heads to the Prom for fun.
Xander loses the award for "Class Clown." Buffy is awarded the new prize of "Class Protector."
Wesley seeks Giles' advice if he should ask Cordelia to dance. He tells him to stop second-guessing and just do it. He and Cordelia slow dance.
Anya and Xander slow dance. Oz and Willow dance as well.
Angel surprises Buffy at the Prom. They slow dance and have their final dance together.