Summer in Paris. A holiday weekend. Antoine, an insurance clerk is looking forward to meeting his wife Hélène, a successful lawyer. He finishes three beers by the time she arrives. They're setting out for the South of France to pick up their children. Unfortunately, on the busiest day of the year. To calm his nerves, Antoine stops occasionally for drinks, determined to transgress the limits. The liquor makes him drive more and more dangerously. The couple fight violently. Hélène, having warned him, leaves. Dashing to the next station, he tries to meet her train but he's too late. Instead, he picks up a strange hitchhiker not knowing he might have already crossed the path of his wife...