Hubert Bonisseur de la Bath (Jean Dujardin), codename OSS117, is a French secret agent who, as we see in the opening sequence, has been fighting the enemies of France since the Second World War. In 1955 OSS 117 is sent to Cairo to investigate the disappearance (and presumed murder) of his old partner Jack Jefferson (Philippe Lefebvre). Cairo is, as the title suggests, awash in intrigue, and soon OSS117 is tangling with Royalist and fundamentalist intrigue, as Nazis and Soviet and English spies.
