A group of international jewel thieves band together to pull off a huge heist in this suspenseful caper film that was shot in Europe, New York, and Brazil. The adventure begins in Rio where a burned out school teacher (Edward G. Robinson) decides to chuck his unfulfilling career and try to steal some of the diamonds he sees being delivered to the gem company across the street from his classroom. Realizing that the theft must be carefully planned and delicately executed, he heads for New York to gain the assistance of an old friend, a crime boss (Adolfo Celi) who then gathers an outlaw group comprised of an electronics expert, a safecracker, a gigolo, and an ex-mercenary. They make their plans and head back to Rio when the city is engulfed in Carnival celebrations. Unfortunately, they quickly learn that the diamond company has installed a nearly impenetrable new security system called Grand Slam 70. While altering their plans, the company secretary (Janet Leigh) gets suspicious and makes a few plans of her own.