Two aging crooks are given two weeks to repay a debt to a woman named The American. They recruit their recently deceased partner's son to help them break into a laboratory and steal the vaccine against STBO, a sexually transmitted disease that is sweeping the country. It's spread by having sex without emotional involvement, and most of its victims are teenagers who make love out of curiosity rather than commitment.
A now-rich woman returns to her poor desert hometown to propose a deal to the populace: her fortune, in exchange for the death of the man who years earlier abandoned her and left her with his child.
Jack and Julie live in a bare flat in Paris. At night, Jack drives a taxi while Julie wanders around the city, and in the day they make love. One day Julie meets Joseph, the daytime driver of the taxi, and soon Julie is spending her nights with Joseph and her days with Jack.
