A smart but friendless sixth-grade boy in 1960's upstate New York gets involved in a real life science fiction story when a mechanical man accidentally trips onto the boy's lean-to in the woods. The boy takes this mysterious stranger into his father's shelter and tries to learn more about the man's mysterious mission. The man, who goes by the name Cross, is reluctant to share details, but he convinces the boy to help him procure a list of items in order to help him save the world. When he is returning with the items, the boy finds police cars and finds out that his mother has shot the man, who has disappeared. That night, the man comes back, clearly dying from his wounds, and explains that in order to save the world from a future nuclear holocaust the boy must carry out his mission and murder US Senator Adlai Stevenson. This will cause Kennedy to go to war with Russia, which the world will survive, and it will avoid the further escalation of nuclear technology in the future, preventing the unsurvivable Third World War. The boy goes to Adlai but is unable to go through with the slaying. No war is triggered, and the senator later dies from a heart attack, confirming the account given by the mechanical man of a worldwide annihilation sometime in the distant future. The boy, as an adult, explains the discord this failure and knowledge of the future has caused him in his personal life.