The movie opens with scenes of an all-women's aerobics class juxtaposed with a classroom of students taking an examination. The movie's two protagonists are featured in these scenes, with Terry Green (Caren Kaye) participating in the aerobics and Bobby Chrystal (Matt Lattanzi) taking, not very well it turns out, his last high school final, in French.
At first, Bobby's main goal for the summer before college appears to be losing his virginity, if not with his unrequited high school crush, Bonnie (Amber Denyse Austin) who dates a college student, then with any takers. Soon, though, the poor results of the French final are in, and Bobby must take a make-up examination and score at least a B (85%) in order to retain his acceptance at his father's alma mater, Yale University. Bobby's father, Mr. Chrystal (Kevin McCarthy), hires Terry, a skilled 30-year-old French tutor, to live in the Chrystal home during the summer and work with Bobby on passing his exam. In addition to her normal compensation, Mr. Chrystal offers to give Terry a bonus payment of $10,000 should Bobby pass. Terry agrees.
Terry and Bobby begin working together but Bobby's lack of interest in both French and Yale soon become apparent. His real goal, he tells Terry, is to attend UCLA and study his true passion, astronomy. Terry is sympathetic but reminds Bobby that wherever he ends up going to college, he will need to pass his French final. With Terry's help, Bobby begins to make some progress.
At night, after she thinks everyone in the Chrystal home is asleep, Terry uses the family's pool to skinny dip. However, Bobby sees her one night and begins watching her regularly (especially after several unsuccessful attempts by his friends and him to have sex with women in increasingly bizarre situations). After one such evening, Bobby follows Terry back to her room, only to have her sneak up behind him and surprise him. Terry gently admonishes Bobby for spying on her but it is clear that they have a mutual attraction. Terry, however, has begun seeing a former boyfriend again, much to Bobby's displeasure.
After yet another evening out with his friends, Bobby returns home to find an upset Terry, who had earlier discovered her boyfriend again cheating on her. They talk briefly and Terry later heads to the pool for her regular swim. Once she completes her lap she sees Bobby waiting for her at the end of the pool. Terry reacts by pulling Bobby into the pool with her and kissing him. Returning to Terry's room together, the two have sex and thus starting an intence love affair. At dawn, Bobby manages to sneak back to his own bedroom where he makes it seem to his father that he has been studying all night.
The affair between Bobby and Terry progresses until the summer's end approaches and he has to take his French examination. Despite Terry's attempts to keep their relationship casual, Bobby has developed serious feelings for Terry and resists her insistence that the affair end once he takes his exam. Matters worsen when Mr. Chrystal, who himself lusts for Terry, sees his son and Terry kissing one night. After Bobby successfully passes the test with a score of an A (91%), Mr. Chrystal reveals to Bobby his promise to pay Terry the $10,000 bonus, implying that Terry's affection for Bobby was driven by greed. Bobby reacts by angrily telling his father that he will be attending UCLA, and not Yale, and storming out to find Terry. Once he finds her, he confronts her with what he has learned, calling her a hooker, leading Terry to slap him and deny his accusation.
Afterward, Bobby seeks out Bonnie, his old crush, and, using his new-found confidence with women, is able to persuade her to begin dating him. In the final scene, Terry prepares to leave the Chrystal home and Bobby approaches her to say good-bye. He begins by apologizing to her for his rash accusations and then telling her that he will forget her. Terry tells him matter-of-factly that he will never forget her. The two share one last kiss, and Terry drives off. Bobby happily leaps into the air, looking forward to the rest of his life.