Ralph, who works in a coal mine in Pennsylvania, is safe underground when a nuclear war destroys the world. After climbing to the surface, he travels to New York City and lives alone until he meets another survivor, Sarah. They gradually form a fragile friendship, but when Sarah expresses interest in a romantic relationship, Ralph is unable to reciprocate due to years of experiencing prejudice that has left him with a persistent fear of interracial relationships. After grappling with this issue, Ralph is about to overcome it when a white man, Benson, arrives in the harbor by boat.