Solo and Illya devise a clever scheme to discredit a Balkan intelligence chief (Werner Klemperer) with a bogus secret gas. With the help of a bankrupt exterminator (William Shatner) and his wife, Illya poses as a fellow countryman and exploits the paranoia of the chief and his bumbling assistant (Leonard Nimoy).

Solo and Illya discover that the world diamond market is being affected by a gang of English criminals headed by Blodgett, who smuggle diamonds inside pudding sold unwittingly by Victoria Poque. They enlist the aid of a master diamond thief, Rafael Delgado. Solo and Victoria end up in Brazil, with Solo tied to the front of a cannon and about to be executed.