Fact1: Ann Rick and Karen leave suburban Los Angeles on camping trip, Fact2: family attempts to return to rescue Ann 's mother, Fact3: Johnson and wife are neighbors but for long, Fact4: Harry and Rick discover teenage girl in room kept as sex slave, Fact5: Marilyn she returns with them back to cave
Output: Harry Baldwin Ray Milland, his wife Ann Jean Hagen, their son Rick Frankie Avalon, and daughter Karen Mary Mitchell leave suburban Los Angeles on a camping trip. The Baldwins notice unusually bright light flashes coming from a great distance. Sporadic news reports broadcast on CONELRAD hint at the start of an atomic war, later confirmed when the Baldwins see a large mushroom cloud over what was Los Angeles. The family initially attempts to return to rescue Anns mother, who lives near Los Angeles, but soon abandons the plan as panicked people climb over one another to escape the fallout from multiple nuclear explosions. Witnessing the threads of society being torn a part, Harry decides the family must find refuge at their secluded vacation spot. Along the way, they stop to buy supplies, and meet hardware store owner Ed Johnson Richard Garland, who wont let them take a handgun theyve purchased because of state law. They also encounter three threatening young hoodlums, Carl Richard Bakalyan, Mickey Rex Holman, and Andy Neil Nephew, on the road, but manage to drive them off. After a harrowing journey, the Baldwins reach their destination and find shelter in a cave, while they wait for order to be restored. On their portable radio they listen to war news and learn what is left of the United Nations has declared this to be Year Zero. Harry and Rick find that Johnson and his wife are their neighbors, but not for long; they are killed by the thugs. While doing laundry Ann drops a blouse in a stream which gets the attention of two of the thugs encountered earlier. As Karen sits nearby reading a book the thugs accost her; rape is implied. Ann scares the thugs off with a rifle then runs to Karens side to comfort her. The two escape returning to the cave, where it is confirmed Karen was raped. Upon hearing what happened, the Baldwin men go in search of the thugs finding them at a farm house. They confront them, where Harry shoots both dead. He and Rick hear noise and discover a teenage girl, Marilyn Joan Freeman, in a room kept as a sex slave. When questioned she tells them she lives there and her parents were murdered by the thugs. Freeing Marilyn, she returns with them back to cave, where she is cared for by Ann. Some time later Rick is out with Marilyn chopping wood. Carl, the third hoodlum, sneaks up behind Marilyn and forces her to drop the rifle she is holding, and begins to question her about what happened to his brothers. Rick tells him to back off and throws a piece of wood at him while Marilyn breaks away she grabs the rifle then shoots Carl dead. In the midst of struggle Carl fires a shot hitting Rick in the leg. Marilyn returns to the cave to get Ricks family and with her help they look for a doctor she knows in Paxton. On the drive there the group hears the enemy has asked for a truce and Year Zero is ending. They find Doctor Strong Willis Bouchey, billed as Willis Buchet. He does what he can for Rick, who has lost so much blood he needs a blood transfusion and must be taken to an Army hospital more than a 100 miles 160 km away or he will die. Along the way the group encounters an Army military patrol that is reestablishing order. After a tense meeting with two soldiers the group is allowed to continue. Watching them depart, the soldiers note they are among the good ones who escaped radiation sickness by being in the mountains when the bombs exploded. As the family drives on, a closing title card states: There must be no end – only a new beginning.