THE WORLD, THE FLESH AND THE DEVIL

Black mine inspector Ralph Burton becomes trapped in a cave-in at a Pennsylvania coal mine. He can hear rescuers digging towards him, but after five days they slow down and then stop completely, along with the drainage pumps keeping the shaft from flooding. Ralph frantically digs his own way out, but upon emerging from the mine, he finds a world devoid of any people, living or dead. Discarded newspapers provide an explanation: one proclaims "UN Retaliates For Use Of Atomic Poison", another that "Millions Flee From Cities! End Of The World". Ralph later plays tapes at a radio station and learns that an unknown country had dispersed large quantities of radioactive sodium isotopes into the atmosphere. The resulting lethal dust cloud spread around the world, killing every human who came into contact with it over a five-day period before the isotopes decayed into a harmless state.

Ralph travels to New York City in search of survivors, but in vain. He restores power to a building where he takes up residence. To stave off loneliness, he takes in a pair of mannequins. As the solitude starts to become intolerable, he throws a mannequin off the building, and hears a scream. Sarah Crandall, a White woman in her early twenties, had been living in the city and surreptitiously observing Ralph for some time, but was afraid to reveal herself. She screamed because she thought Ralph had committed suicide.

Ralph, an engineer, gets utilities working again and raises their standard of living, but the two remain in separate apartment buildings. Even as they become friends and grow closer, vestiges of racial division become evident when Sarah casually uses the phrase that she is "free, white, and 21" to describe her ability to make decisions. Ralph describes the phrase as "an arrow in my guts." In the same conversation, Sarah laments that "there is nobody left to marry." Resentful, Ralph refuses Sarah's suggestion that she move into his apartment building. Ralph maintains his distance when it becomes clear that Sarah is developing stronger feelings for him, unsure how she will react if they discover others alive. Despite living in a post-apocalyptic world, tensions remain that were instilled by the mores earned in a racially segregated American society.

Ralph regularly broadcasts on the radio in the hope of contacting other survivors, and eventually receives a transmission in French, confirming there are others. One day, ill white man Benson Thacker arrives by boat. Ralph and Sarah nurse him back to health, but once he recovers, Ben sets his sights on Sarah and sees Ralph as a rival. Ralph is torn by conflicting emotions. He avoids Sarah as much as possible to give Ben every opportunity to win her affections, but cannot quite bring himself to leave the city.

Ben finally grows tired of the whole situation, realizing he stands little chance with Sarah as long as Ralph remains nearby. He warns Ralph that the next time he sees him, he will try to kill him. The two armed men hunt each other through the empty streets. Finally, Ralph passes by the United Nations headquarters, climbs the steps in Ralph Bunche Park, and reads the inscription "They shall beat their swords into plowshares. And their spears into pruning hooks. Nation shall not lift up sword against nation. Neither shall they learn war any more", from the Book of Isaiah. He throws down his rifle and goes unarmed to confront Ben, who in turn finds himself unable to shoot his foe. Defeated, he starts walking away. Sarah appears. When Ralph starts to turn away from her, she makes him take her hand; then she calls to Ben and gives him her other hand. Together, the three walk down the street to build a new future together. The film ends not with "The End" but with "The Beginning."

The central triangle reaches a standoff as the two men confront each other, weapons drawn, but ultimately they choose not to resort to violence and walk away together with Sarah into the abandoned city.

The film’s conclusion rejects violence and suggests a fragile hope for humanity’s future, as the survivors choose cooperation over conflict. The ending underlines the persistence of social divisions, but also the possibility for change when old rules no longer apply. By refusing a violent resolution, the film asks whether people can transcend the prejudices and rivalries that outlived civilization itself.