In the wake of a mysterious disaster, the human race has practically died out, and there are only two human beings left on Earth. The last man, Bertie, is a 56-year-old former firefighter. His life is full of fake people, played by robotic biops, who can change their appearance and play the roles of his girlfriend, friends, pets, neighbors, etc. Ever since the second-to-last man on Earth died, Bertie has been in a funk, drinking excessively, and asking about his late wife, Kathy. His girlfriend biop can take the form of any woman, but her attempts to play Kathy make him upset. In order to lift his spirits, the lead biop on his team, Aunty Em, decides to create a Christmas time scenario for Bertie. But she is alarmed when he asks for a gun for Christmas. Aunty Em assigns some biops to play flying reindeer that take him to a fake mall, where more biops pretend to be holiday shoppers. The girlfriend biop assumes the body of Donna Reed from "It's a Wonderful Life," but Bertie pays no attention to her, and she grows increasingly upset by his rebuffs. Inside the mall, Bertie finds the last woman on Earth, Ellen Marelli, smashing lightbulbs on the floor, while the lead biop of her team, Dr. Watson, sweeps away the shards. Ellen is older than Bertie and has trouble remembering him. Bertie invites her to join him on the Christmas shopping trip, which lifts both of their spirits. But Ellen becomes agitated and accuses Aunty Em of ruining everything. When Dr. Watson tries to take Ellen home, she calls Bertie 'Daddy', and asks him to secretly play along with her. Bertie's mood noticeably improves after the shopping trip, but he continues to ignore the girlfriend biop. On Christmas Day, Aunty Em gives Bertie an unloaded gun, but the girlfriend biop storms in, looking like Kathy, and hands him a load of bullets. As Aunty Em desperately begs her to leave, the girlfriend asks him to shoot her. Bertie asks if everybody else is dead, besides him and Ellen, and the girlfriend bursts into tears, even though biops aren't supposed to cry. Aunty Em confirms that Bertie is the last man on Earth. Bertie tells them that it's important he doesn't forget this truth, as it is crucial to his identity. He apologizes for his bad mood and promises not to give up. He makes amends with the girlfriend and asks her to keep the bullets safe for him.