In 1965 Queen City, Bootsie Goodhead and her friend, Rhonda, join classmate Rick McKay in his Ford Thunderbird, as they and their fellow students converge on Taft and Adams High School, affectionately known as “T&A.” When Rick learns that the school is offering breast examinations, he enters the infirmary disguised as a doctor and begins to examine his first patient. As the girl removes her brassiere, he is caught by the school nurse and given detention. Meanwhile, comely French teacher Miss Boudoir becomes sexually aroused by the sound of her own voice and excuses herself from class, leaving teenage millionaire Brent Van Dusen III in charge. Brent places a scale model of the Eiffel Tower over his crotch and aims the tip at homecoming queen Purity Busch, the school’s only remaining virgin. Miss Boudoir catches Brent and he is given detention. Transfer student Tim Stevenson asks Purity for directions to the boys’ gym, but when she leads him into the girls’ locker room, he is given detention as well. In the cafeteria, Bootsie and Rhonda make suggestive comments to Melvin Jerkovski, and he gets a detention after Miss Shivers, secretary to Principal Stuckoff, finds him masturbating in the meat locker. School nerd Howie Bates is also detained after Mrs. Roach, the wheelchair-bound home economics teacher, discovers that he has arranged all of the school’s convex mirrors to reflect the underside of the cheerleaders’ skirts as they pass in the hallway. That afternoon, the five detainees serve their sentence outside Principal Stuckoff’s office, as he dotes on Purity. She drops a stack of papers on the floor, and when the boys rush to her aid, the principal increases their detention to five days. The following day, the boys make a pact that at least one of them will “have a shot” at ending Purity’s virginity. Tim makes the first attempt, visiting the Busch home late at night. When Purity’s father, Ward, hears Tim outside, he grabs his rifle, believing a Communist invasion is underway. Tim gains entry to the house, but inadvertently makes love to Purity’s sexually frustrated mother, June, and narrowly escapes when Ward returns to the bedroom. Bootsie hears of Tim’s exploit the next day and invites him on a date to the drive-in movie theater. Howie concocts a plan to seduce Purity through hypnosis. He taps into the school’s public address system and summons Purity to the swimming pool, supposedly at the behest of Principal Stuckoff. Finding no sign of the principal, Purity leaves the pool moments later. The girls’ physical education class appears poolside as Howie begins his hypnotic incantation from a nearby closet. They recognize Howie’s voice and pretend to be under his spell when he makes his appearance, before they attack him and throw him into the pool. That night at the drive-in, Tim’s date with Bootsie is interrupted when he discovers his sister, Trisha, in an adjacent car with Brent. The two boys brawl while Bootsie watches from the car with bare breasts pressed against the window. Melvin makes the next attempt on Purity by having his friends bury him in the sand at her favorite spot on the beach. Using a facemask, a straw, and a soda can, Howie builds a device that enables Melvin’s vision and breathing. Melvin spends the entire day under the sand, trampled by joggers and urinated upon by dogs. Meanwhile, at school, biology teacher Sarah Bellum keeps Brent after class to make love to him in the supply room. Their tryst ends prematurely when a volatile chemical is ignited, and Sara runs topless into the hallway. On the beach, Purity spreads her blanket over Melvin’s prone body and removes his breathing straw from the sand. Desperate for air, Melvin rises to the surface and Purity runs screaming from the beach. Later, the boys visit a sex shop run by Vince, the Prince of Porn, and Brent purchases a jar of aphrodisiac known as “Spanish fly.” The following day, during the dedication of the school’s new airplane repair shop, Brent initiates an orgy by diluting the drug in the punchbowl. However, Purity continually frustrates him by never taking a drink. At the bowling alley, the boys challenge Bootsie, Rhonda, and their friends to a game of strip bowling, which ends with Howie’s penis getting caught in a bowling ball. Rick enters the home economics class under the guise of Miss Farquahr, a substitute teacher, after leaving Mrs. Roach bound and gagged in a broom closet. Rick proceeds to measure the girls for their homecoming dresses, starting with Purity. Mrs. Roach breaks loose, wheels into the classroom, and engages in a mock bullfight with Rick, who uses his skirt as a cape. She makes a final charge as Rick leaps out of her way, and crashes in the hallway. The boys attend a strip club, where they photograph Mr. Stuckoff in a compromising position with one of the performers, and use the picture as leverage to end their detention. Determined to humiliate Purity, Howie enlists his friends in a scheme involving a powerful electromagnet. Rick, Bootsie, and Rhonda remove Purity’s dress from the home economics classroom and lace the fabric with metal threads, while Howie builds a makeshift generator. At the homecoming assembly, Purity sings the national anthem as Howie enables the magnet, which removes all metal objects from the room, including Purity’s clothes. She stands naked to her waist in front of the entire school.