In May 1969, high school senior David Kessler lives with his parents and 14-year-old brother Charlie in a large Beverly Hills, California, house, where they communicate almost exclusively with a ubiquitous video intercom system. As David approaches the final weeks before graduation, the Vietnam War is a constant presence on radio and television. David makes it clear to his best friend, Mark, that his priority is to find a place to lose his virginity to his girlfriend, Margaret. Mark suggests David pursue Tracy, a girl David has known since they were six. At school, David runs track, writes for the student newspaper, and hopes to be accepted by Stanford University. Mr. Phinney, the journalism teacher, rejects David’s final column and asks him to rewrite it because it expresses opposition to the war. After school, David and Mark work at a takeout chicken restaurant called "Chicken on the Run," where they smoke marijuana and engage in hijinks under the nose of the proprietor, Max "Cap" Ober. Later, at David’s parents’ house, he and Margaret are being intimate on the couch, but she gets spooked. She complains that David smells like chicken and insists that he find a “safe place” for sex before they go any further. The next day, after David receives detention from vice principal Mr. Nastase for not having a hall pass, David and Mark steal a batch of blank passes, the time-stamp clock, and a rubber stamp with Nastase’s signature from the office. That afternoon, at David’s final track meet, an official tries to keep David from competing because of the length of his hair. David rallies the other athletes for a boycott and the official backs down. David easily wins the 100-yard dash, but is denied the school record by the team manager, Saul, who breaks the stopwatch. Later, David’s friends goad him into asking the sexually-active Charlie for help in finding a “safe place.” Charlie offers a guest room above the garage belonging to his girlfriend’s parents, the Worths, but asks for marijuana in return for the favor. Back at "Chicken on the Run," David questions Mark about his mystery girlfriend. Mark is evasive, saying she works nights. David convinces Cap to let him leave early for his date. That evening, David gets a reluctant Margaret into the guest room, but doesn’t have a condom. David asks her to wait while he goes to Mark’s house to borrow a “balloon.” David returns to the guest room to find that the Worths have returned early and Margaret is gone. A neighbor mistakes David for a peeping Tom and he is chased through several yards by a pack of dogs and eludes the police. He returns to Mark’s and attempts to call Margaret, who can’t or won’t come to the phone. David is still feeling amorous, so Mark dials Tracy’s number and David asks her to meet him at his house. There, Tracy tells David that Margaret isn’t as innocent as David thought. Tracy realizes she was David’s second choice, and tells David that she doesn’t want to get involved until he figures out his feelings for Margaret. The next day at school, Mark tells David that Margaret is taking birth control pills. David confronts Margaret and they argue. Margaret breaks their date to the prom saying she never really wanted him. David goes to class and discovers that the police have Mark in Nastase’s office after catching him with a joint. David confesses to stealing the passes and the clock. Nastase suspends David and orders him to rewrite his anti-war column, which he had resubmitted after only changing the title. At home, David’s mother tells him he’s going to be drafted if he doesn’t straighten up. David goes to work and learns that the brother of a female co-worker, Maddy, was killed in Vietnam. Cap sends Maddy home and orders the boys back to work, but David has had enough and quits. Cap is shocked and tells him he had planned to turn the business over to David one day. David tells him he’s going to college and leaves. David sees Maddy waiting for a bus and offers her a ride, but she declines. Frustrated, David returns to school and sneaks his column into print. Later, David confesses to Tracy that he really wanted to go to the prom. Tracy tells him that they don’t need the prom and she wants to be his date for the after-party. Margaret arrives at the party with David’s friend Stuart and Mark brings his “mystery girl,” a 14-year-old prostitute named Vanessa. Charlie crashes the party and hits it off with Vanessa. Later, Tracy tells David that Vanessa is actually Pam, a 19-year-old married to a helicopter pilot in Vietnam. Pam lied so that Mark wouldn’t fall in love with her. Margaret tells David that she doesn’t like seeing him with Tracy, wishes she would have gone to prom with him and not Stuart, and doesn’t blame David for the debacle at the guest room. Margaret kisses David as Stuart walks in. Stuart punches David, knocking him down. David and Tracy go the Kessler house, but Stuart calls to say that Charlie was injured walking through a glass door at the party. At the hospital, David yells at Margaret for not taking care of his brother. Stuart apologizes for hitting David and says Margret isn’t worth it. David and Tracy locate Charlie, who is registered under an alias because he is intoxicated. The following morning, David arranges to have Cap, pretending to be Charlie’s Arizona rancher father, check Charlie out of the hospital so he won't get in trouble. At school, Nastase and Phinney, the journalism teacher, discover David’s story in the newspaper. To avoid negative publicity, they decide that David won’t graduate with his class, but will have his diploma mailed to him. Graduating means David is able to go to college and have a deferment from the draft. David finally loses his virginity to Tracy and vows to destroy his family's intercom system.