Later that night, one of Buffy's classmates, Theresa, is walking home alone when she bumps in Angel, who offers to walk her home. Meanwhile, Buffy and Giles investigate Lover's Lane in the woods, hoping to find the werewolf and bring it back alive, for it is still a human twenty-eight days out of the month. Buffy gets trapped in a net that lifts her to the top of the trees. As she calls for help from Giles, a poacher named Cain appears with a shotgun. After realizing that his catch is not a werewolf, he cuts the net down, and Giles helps Buffy out. Cain explains that he hunts werewolves to make money. He then asks them if they know where else the teenagers might hang out, since werewolves are attracted to sexual heat. Buffy feigns ignorance, so Cain leaves and goes off on his own. Buffy and Giles then drive towards the Bronze, which fits Cain's description perfectly. As they arrive there, dozens of frightened teens evacuate the Bronze, for the werewolf has already arrived. Buffy runs inside by herself and pulls a chain out of her backpack. She tries to tie up the werewolf, but it breaks free of the chain and escapes. While Buffy and Giles deal with Cain, who is upset that she tried to capture it instead of kill it, the werewolf wanders down the alleys when it discovers Theresa's body. There are two bite marks on its neck, and all the blood has been drained from its body. The werewolf looks up and sees Angel. The two growl at each other, but do not attack. Angel eventually backs off and disappears.
Early next morning before sunrise, Buffy and Giles hear on the radio that Theresa was found dead, and her murder may be linked to the werewolf. They now have only night left before the werewolf goes into remission for the remainder of the month. As the sun rises, the werewolf slowly transforms back to human form while it is sleeping. Once all the hair fades away to reveal flesh, we see that the werewolf is Oz. After waking up and realizing that he is naked in the woods, Oz suspects that he may be the werewolf. He goes home and calls his aunt. Oz asks her about his cousin Jordy, who bit him recently. Apparently, his aunt knows that Jordy is a werewolf, and since he bit Oz, the curse has been passed along. Oz goes to school that day in a daze, and he is horrified to learn that he may have killed Theresa the previous night. Xander suspects that Larry may be the werewolf, so he leaves to question him in the locker room. Willow invites Oz to help her do some research later that night, but Oz refuses and runs off, leaving Willow upset over his apparent change of heart. In the locker room, Xander confronts Larry in the locker room. Xander tells him that he knows the secret that Larry has been hiding, only to find out that Larry's secret is his homosexuality. Misunderstanding Xander's words, Larry now believes that Xander is also gay, but assures him that their secret is safe between them. Feeling relieved and better about himself, Larry thanks Xander and walks off.
Realizing that the police reports never mentioned anything about Theresa being mauled, Buffy and Xander visit the funeral home and inspect Theresa's body. Sure enough, they find two bite marks on her neck, signifying death by vampire. While Buffy signs the guestbook, Theresa suddenly gets up behind her, only now her face is that of a vampire. In the middle of their fight, Theresa throws Buffy off guard by saying that Angel sent her. Luckily, Xander is able to stake her through the back before she can take advantage of Buffy's disoriented state. After being helped up, Buffy embraces Xander for a short while, expressing her fear of Angel's relentlessness. She then realizes her position, gathers herself together, and leaves, with Xander following behind. Elsewhere, Oz knows that he must not be able to leave the house that night, so brings out a box of chains and shackles. Before he can lock himself up, Willow knocks on the door. She is obviously upset by his decision to stay home and do nothing by himself instead of spending the time with her. Oz tries to warn her of the danger, but it is too late, for his transformation has already begun. Willow screams and runs out of the house, while the werewolf chases her down the block and into the woods. Before he can attack Willow, a different scent catches the werewolf's nose, so he leaves Willow alone. She runs off to the library, where Giles is loading up a tranquilizer gun. Willow tells Giles and Buffy that Oz is the werewolf, so they rush out to the woods. Buffy kicks the shotgun out of Cain's hand just before he pulls the trigger. After knockin Cain down, Buffy fights the werewolf, which prevents Giles from getting a clean shot. Buffy is then knocked into Giles and Willow. As the werewolf charges them, Willow grabs the tranquilizer gun and shoots him, causing him to stumble back and collapse. As Cain gets up, Buffy bends his gun with her bare hands, then orders him to leave.
The next day, Oz tells Willow that he'll be fine, as long as he locks himself up around the full moon every month. To his surprise, Willow is still interested in continuing their relationship. As she leaves, Willow kisses Oz for the first time.