Kenneth O'Neil travels back to 1962 to prevent the world's first nuclear war. Upon arrival, he suffers from amnesia. As he struggles to remember what he should be doing in this unfamiliar world, he falls in love with teacher Louise Jensen. He is unaware a Chinese agent, Hwang Ko, has followed him to the past. By killing O'Neil, Ko will protect both the future of the woman he loves and the history that led to China's supreme rule.