Stanislav Petrov, a retired Soviet lieutenant colonel, lives a quiet, solitary life in a small apartment in Fryazino, Russia, haunted by the weight of a single, life-altering decision he made decades earlier. In 1983, while serving as the commander of a top-secret nuclear command post, Petrov was faced with a terrifying alert: the system indicated that the United States had launched a nuclear strike against the Soviet Union. With only minutes to decide whether to initiate a retaliatory attack that would have triggered a global nuclear war, Petrov chose to trust his intuition and report the alert as a false alarm, a decision that ultimately saved millions of lives. Now, years later, he is approached by a group of filmmakers who want to document his story, forcing him to confront the trauma of that night and the profound, lingering impact of his actions on the world.