A discredited expatriate United States professor, Theo Wilkins (Edward G. Robinson), has called on a young protégé and sophisticated thief, Paul Mason (Rod Steiger), to come over from the US to the south of France and help him pull off one final heist. He has masterminded a caper to steal $4,000,000 in French francs from the underground vault of the casino of Monte Carlo, Monaco. Wilkins has recruited a team of thieves – including Melanie (Joan Collins), an exotic dancer – but he needs someone he can trust, Mason, to keep them all in line during the crime.