Buffy and Angel spar until Buffy pins him and holds a breadstick to his heart. They talk, and Buffy reveals her plans to go to an ice show with her father for her 18th birthday. That night in the library, Giles is quizzing her on crystals and having her concentrate on staring at them. Later, on patrol, Buffy's strength suddenly deserts her and she is nearly killed by a vampire with her own stake.
Buffy's worried about her powers, and talks to Giles about it while trying to throw knives at a target but missing terribly. Meanwhile, Quentin Travers, the head Watcher, is setting up a "test" for the Slayer, assisted by two men named Hobson and Blair. She is to be locked in a building, without any powers, and defeat Zachary Kralik, a powerful and insane vampire. Giles urges Travers to stop the test, but it does no good. At home, Buffy is disappointed to find that her father can't come and take her to the ice show for her birthday. While she tries to get Giles to take her to the ice show, Giles has Buffy stare into a crystal where she then falls into a trance. He injects her with a needle filled with muscle relaxant and adrenaline suppressors.
After Cordelia fights off an aggressive suitor who had knocked Buffy down, Buffy really begins to worry, and enlists the help of her friends to figure out what's wrong. Buffy visits Angel and he gives her a book for her birthday (Sonnets From the Portuguese, by Elizabeth Barrett Browning). She tries to sound enthusiastic about it, but losing her powers has really begun to bother her. He tells her about how he saw her before she was the Slayer and how he loved her from the second he first saw her. Kralik has the chance to break out of his strait jacket while Blair is getting his pills and water. He then turns Blair into a vampire and when he wakes up, he completely frees Kralik from his restraints.
Giles goes to find Quentin at the Sunnydale Arms building, but instead finds Kralik missing and Hobson dead. Buffy, walking home alone, is confronted by two men looking for a lap dance and then by Kralik. Blair chases her until Giles drives by and picks her up. At the Summers' home, Joyce hears a noise out front and goes to check it out where she then finds Kralik wrapped up in Buffy's jacket. Giles tells Buffy that she's lost her strength due to the injections of muscle relaxant he'd been giving her, and about the rite of passage. Buffy is very angry and tells him she doesn't know him anymore, and he should stay away from her or she'll kill him. Cordelia shows up and drives Buffy home, where she then finds a picture of her mother in the hands of Kralik.
Buffy goes to the Sunnydale Arms building, beats Blair into unconsciousness and then is chased by Kralik until his need for his pills becomes unbearable. Buffy steals them away, and slides down a laundry chute where she finds her mother tied to a chair. Kralik breaks through the door and grabs his pills from Buffy, washing them down with a nearby glass â which Buffy had filled with holy water, causing him to burn from within. With Kralik destroyed, Buffy frees her mother. Giles arrives and stakes Blair.
Back at the library, Quentin congratulates Buffy on her accomplishment, and then Buffy tells Quentin that he better be gone by the time she gets her powers back. Quentin tells Giles that he's fired because he's grown too close with the Slayer; his relationship with her is as more of a father than a Watcher. He tells Buffy that a new Watcher will be assigned to her and warns Giles not to interfere before finally leaving. Buffy, grateful that Giles lost his job for her, allows him to tend her wounds. The next day, Buffy celebrates her birthday with peanut butter and jelly sandwiches and her close friends. When Buffy, minus her strength, can't open the peanut butter jar, Xander offers to help, but he can't do it either.