Plot summary

On board a moving train heading to Las Vegas, God (in the form of a gray-haired, bearded man wearing a white suit) and Satan (in the form of a tall, dark tuxedo-clad man) are seated in a small compartment, disputing what they each offer to humankind. Also aboard the train is a group of young people having a party. God and Satan discuss the fate of three individuals as they watch their stories unfold..."The Case of Harry Billings"Harry Billings (John Phillip Law) is an alcoholic and hedonist salesman who accidentally kills his wife while driving recklessly. He is arrested and taken to a mysterious psychiatric hospital where is placed under hypnosis by a Dr. Fargo (Sharon Ratcliff) and Dr. Brewer (Arthur M. Braham). A young couple stop there to use the phone after becoming lost, and are kidnapped and murdered by Otto (Richard Moll), an orderly.Meanwhile, the staff use a hypnotized Harry to lure various people to the hospital, including a bartender and a young woman, only to be brutally murdered. The victims' corpses are then used for organ harvesting. Dr. Fargo turns on Brewer, spiking his drink with a sedative. Dr. Fargo lobotomizes Brewer, leaving her in sole control of Harry, with whom she has become romantically involved. Harry defies Fargo and kills Otto while attempting to escape. Meanwhile, a lobotomized Brewer enacts revenge by performing vivisection on Fargo."The Case of Gretta Connors"Gretta Connors (Meredeth Haze), is a young and struggling aspiring actress working at an amusement park. Gretta meets and falls in love with an austere, middle-aged man named George Youngmeyer (J. Martin Sellers). George exploits Gretta by forcing her into pornographic films. Glenn Marshall (Rick Barnes), a medical school student, becomes enamored of Gretta after seeing one of her films, and tracks her to a Manhattan bar owned by George, where she performs as a pianist. The two fall in love, and a jealous George enacts a revenge plot by recruiting the two into a death cult of which he is a member. The cult subjects Glenn to various Russian roulette-style death games. When Gretta and Glenn are to be married, George kidnaps them and subjects them to another death game using a wrecking ball, but the game ends in one of the cultists dying instead."The Case of Claire Hansen"Claire Hansen (Faith Clift) is a devout Catholic surgeon plagued by nightmares about Nazis. Meanwhile, police Lieutenant Stern (Cameron Mitchell) attempts to help the elderly Abraham Weiss (Marc Lawrence) track down a group of Nazis who murdered his family during the Holocaust, and whom Weiss believes fled to the United States during World War II, where they assumed new identities. Stern is skeptical of Weiss's claims, as the individuals Weiss identifies do not appear to have aged since 1944. Weiss takes it upon himself to enact revenge by tracking the group to a large mansion, but is killed after encountering a demonic-looking woman. Claire later performs Weiss's autopsy, and finds a mysterious "666" tattoo on his abdomen, indicating the mark of the beast. Claire's atheist scientist husband is met by Papini, a man branded with this tattoo, but her husband dismisses him.Papini attempts to stop the Nazi group-who are in fact a cult of demonic apprentices to the Devil-but is captured by a monstrous creature and dragged into the earth. The cult begins preying on Claire's husband, luring him to an island to meet with their leader, Olivier. He is killed when he refuses to accept Satan as his master. Later, Claire accidentally hits Olivier with her car near the cult's mansion. At the hospital, she performs a surgery on him, during which her assistant is compelled to kill him, and stabs him on the operating table. Realizing Olivier is a servant of the Devil, the women begin to remove his organs as he flies into a violent rage. Olivier re-manifests in the operating room, his body restored, and Claire observes that the vivisected body on the table is now that of her assistant, dead. Claire screams in horror as a coiffed Olivier walks out of the hospital.On the train, God and Satan vie for control of the fate of its passengers; Satan plans to crash the train and send all its unwitting passengers' souls to hell. Satan causes the train to derail, apparently killing everyone aboard, but God intervenes and, instead, the train is seen ascending a track into the sky.