High school student Scott Howard is seventeen years old, sick of being average and wishing he were special. His father runs a local hardware store. Scott plays basketball for his high school’s team, the Beavers, with a not-so-good win-loss record. The girl of his dreams, Pamela Wells, is dating Mick, a jerk from an opposing high school team, the Dragons. After another of the team’s losses, Scott begins to notice strange changes to his body. While at a party, Scott keeps undergoing changes and eventually he returns home, locks himself in the bathroom, and undergoes a complete change and becomes a werewolf, while his father demands that he open the door. He tries to refuse, only to finally give in and obey, to find his father has also transformed into a werewolf.
Harold never told his son about the condition because “sometimes it skips a generation” and he was hoping it wouldn’t happen to Scott. Scott first reveals his transformation to the public at one of his basketball games, after getting pinned in a pile-up. After momentarily stunning the crowd with The Wolf, Scott goes on to wow them with his basketball skills and he finishes the game with a quadruple double.
Scott subsequently learns to use his family “curse” to gain popularity at school, becoming the team’s star basketball player, and learns to transform at will between his normal self and The Wolf. His basketball team goes from last to first, and Scott begins spending most of his school time as The Wolf. He also wins the heart of Pamela while ignoring the affections of his best friend, Boof, who has loved him since childhood.
Scott’s other best friend Stiles, a party animal with an entrepreneurial streak, quickly cashes in on Scott’s new-found popularity, selling Teen Wolf T-shirts and other merchandise. Stiles’ “wolfmania” reaches such extremes that he trades in his own vehicle for a stepvan dubbed “Wolfmobile.”
After a freaky encounter with Mick at the Spring Dance that almost turns violent, Scott wishes to be himself. During the final basketball game (Beavers vs. Dragons again), Scott refuses to “wolf out” and insists on winning the game on his own. Coach Bobby Finstock tells Scott that the team is doomed to fail without The Wolf, but Scott is able to prove him wrong. In a dramatic ending, and with the help of four fouls from Mick, Scott is able to rally the team back to within a point as time is expiring. Scott is fouled one last time by Mick on the final play and given two shots. In a clear violation of the rules, Mick is able to stand underneath the basket as Scott attempts his foul shots. Scott makes both baskets and the Beavers win the game by one point.
Pamela attempts to get Scott’s attention after the game is over, but he passes her by to hold Boof in his arms, kissing her passionately.