Through Jean, an ex-con who is now a croupier at the casino in Deauville, Bob's friend Roger, a safecracker, learns that, by 5:00 in the morning on the day of a big horse race at the nearby track, the casino safe is expected to contain around 800 million French francs in cash. As Bob has recently had a run of bad luck, he forms a plan to rob the safe, convincing a man named McKimmie to finance the preparations and recruiting a team of professional criminals to carry out the heist. Jean gets the team detailed floor plans of the casino and the specifications of the safe, and he buys jewelry for his avaricious wife, Suzanne, with some of the money he is paid for his services.