J. Lee Thompson (The Guns of Navarone) directed this Cold War action thriller. Gregory Peck is the American Dr. John Hathaway, a Noble Prize-winning scientist, teaching at a university in London. Lieutenant General Shelby (Arthur Hill), from the American Embassy, asks Hathaway to go on a mission to Communist China to obtain an enzyme, being developed by his old teacher Soong Li (Keye Luke), that permits crops to grow in any climate. Since the country holding the formula to this growth enzyme would be able to control the world, Shelby tells Hathaway that both the United States and the Soviet Union are anxious that the enzyme not stay in China. Hathaway doesn't want to go because of a burgeoning love affair with attractive professor Kay Hanna (Anne Heywood) and an opposition he holds to American foreign policy. But a call from the President changes his mind, and he is off to China. A transmitter is placed in his skull so that he can communicate with London. But Hathaway doesn't realize that the head implant can also be detonated from London, if necessary, and blow Hathaway's brains out. In China, Hathaway works with his old mentor Soong Li to perfect the enzyme. As they are near completion, the Red Guard storms the laboratory and attack Soong Li because of his opposition to the new movement in China, and Hathaway has to flee the country. Detecting the transmitter in Hathaway's head, the Chinese are in full pursuit. Hathaway makes it to the Sino-Soviet border, but then Shelby decides to activate the explosive device in Hathaway's head once he crosses over into Russia.