The eldest daughter of a Professor of Psychology at a large conservative university causes havoc, and great embarrassment, for her father with her free-willed and uninhibited lifestyle.
Dr. Jonathan Kingsley is a university professor of psychiatry. He recently learned that he is short-listed to head up the psychiatry department. The committee wants to be assured that he has a stable family life, so he and his wife Alice are hosting a poolside party at their home.
Jonathan and Alice have two teenage daughters, Linda (17) and Abby (14). Linda is about to graduate from high school. To her parents' horror, she is arrested during a riot at the university. She hotly defends her right to protest and carry a sign, but unknown to her there was an obscene word on one side. Soon after this, a letter comes from her gym teacher that Linda is doing failing work. Her parents can't understand how anyone could fail gym. Also, the committee learns of Linda's arrest and began to have their doubts that her father is the appropriate choice.
Linda's boyfriend is her next door neighbor, Freddie Fleischer. His father is the Kingsley family doctor. Freddie plays the trumpet while sitting in his bedroom window, causing the peace of the neighborhood to be disturbed. Linda is tired of Freddie and wants to break it off. He acts nice around her parents but when they're alone, he is all over her trying to "score."
Jonathan is writing a book and his research assistant, Richard Merrick, frequently comes to the house. Richard is several years older than Linda and it seems they are just friends. Jonathan resents Richard's frequent suggestions on how to improve the manuscript.
Linda's parents are upset over her messy room. She sees nothing wrong with it. There are so many dirty dishes in her bedroom that Alice doesn't have enough for the upcoming party. Rather than clean Linda's room, Jonathan tells her to just buy a new set of dishes.
The Kingsley parents meet with the gym teacher, who shows them fake absence notes written by Linda and signed with their names. She claims that her father has wrecked his car, had a heart attack, and used her for LSD experiments. They have already taken away her car after yet another speeding ticket. Her allowance was stopped for another infraction. There is really nothing left they can take away from her. In despair, they decided to take away Freddie. Linda is actually relieved to break up with him, but he takes it badly. Night after night he plays "Taps" on his trumpet.
An artist friend of Linda's, Bartholomew Smuts, comes to her pool party to do some sketches for a picture of her that he is painting. He is older than the other boys and drives a motorcycle. Jonathan is disgusted with him, especially when he denounces the Kingsleys' Matisse painting as a fake.
Linda wants to go with her friends to Catalina over the Fourth of July weekend. Her father refuses to let her go unless she takes a chaperone. In the end, the gym teacher agrees to accompany the group. Unknown to Jonathan and Alice, the teacher meets a man and spends all her time with him, leaving the teenagers to their own devices.
Linda seems to change after the Catalina trip. She actually cleans her room and carries down several baskets of dirty dishes. Jonathan takes this to mean that she is finally growing up.
On the night of the pool party, Dr. Fleischer comes over and wants to know why Linda dumped Freddie. He and Jonathan argue and the doctor reveals that when conducting her physical examination for college, he discovered that she is no longer a virgin. Jonathan is furious and orders him to leave. Then he and Abby anxiously try to guess who is responsible.
Linda dresses up for the party and has many compliments. Merrick asks her teasingly what happened to her jeans and sweatshirt. Linda says she left them at Catalina. He asks her what else she left there.
Despite Jonathan's anxiety, the party is going well and the committee seems impressed. Then Smuts arrives, bringing the painting of Linda. Alice smooths over the awkwardness by telling the guests to gather around and see the portrait. To their shock, she is nude. Jonathan tries to cover the painting with his jacket and loudly announces that Linda couldn't have posed for it. He tries to take it away but Smuts stops him. They accidentally hit the university chancellor and he falls into the pool. Chaos ensures and in his anger, Jonathan reveals what Dr. Fleischer told him. Linda runs upstairs in tears and the guests are so shocked that they don't know what to say.
Jonathan resigns himself to losing the chairmanship. He and Alice try to talk to Linda but get nowhere. She posed for the painting in her bikini and Smuts decided to paint her as a nude.
While talking to Abby, Linda reveals that she had secretly married during the weekend at Catalina. That is why she is no longer a virgin. Before she can reveal the name of her husband, Abby blurts out the truth to their parents. Linda further reveals that she and the man flew to Las Vegas and eloped under assumed names.
After a horrible quarrel with her parents, Linda packs and leaves home, promising to be in touch later. Abby moves into her vacated bedroom. Jonathan and Alice fear they have lost her forever. He vows to have the marriage annulled as soon as he finds out who Linda has married.
The painting was damaged during the party and Smuts brings it back after making repairs. Jonathan believes he has married Linda and attacks him, vowing to prosecute him for taking an underage girl across the state line. Linda arrives with Richard Merrick, who reveals that he is her husband. Jonathan goes after him. Linda screams at them to stop fighting and runs out of the house, jumping in her car and driving off. They try to follow her on Smuts' motorcycle. A wild chase ensures, with Linda's gas pedal sticking and then coming off. She cannot stop the car and they go all the way to the university before she finally manage to turn off the engine. Merrick and Jonathan wreck the motorcycle and end up in the mud. Just then the committee emerges from a building, having voted to make Jonathan the new chairman.
Alice and Jonathan believe that their troubles are over. But Abby's boyfriend comes over to do homework with her. Jonathan realizes the impossible years are starting all over again.
