While on a fishing trip| Harry Baldwin (Ray Milland) and his family hear an explosion and realize that Los Angeles has been leveled by a nuclear attack. Looters andkillers are everywhere. Escaping to the hills with his family| he sets about the business of surviving in a world where| he knows| the old ideals of humanity will befirst casualties. Not one to give up| he holds up a store for supplies and hides the family in a cave.