On Mars, a mass evacuation has occurred and the only man left on the planet is Walter Gripp, who works at a hydraulic project. When he calls in after two weeks and is unable to raise anyone, he drives into town and discovers that every rocket at the spaceport has departed. Walter soon confirms that all of the colonies were evacuated due to the coming war on Earth. He goes to a bar and starts drinking, taking on the role of customer and bartender while complaining about how he was left behind. He fantasizes about the woman he loved from afar, Clara Haslip, and then wanders the town, eating and drinking as he likes.
Walter watches a film in a theater to keep himself company but soon realizes that he's deluding himself. As he goes outside, he hears a phone ring. At first he thinks nothing of it, but then finally realizes that it means someone else is on the plant. He runs to the house but the line goes dead just as he picks it up. Feeling the stress of loneliness, Walter wonders if it's Clara trying to call him. He finally gets a grip on himself, but figures that the other person must be a woman since a man wouldn't bother to call for company. Walter hears another phone and runs to the next house, breaking in. That phone also goes dead but the person at the other end has apparently left a message on the answering machine. However, Walter soon realizes that the message was left from before the evacuation.
When another phone rings, a desperate Walter runs to that house. He answers the phone in time but discovers that it's an automated evacuation message. Walter throws the phone into a sink filled with water and walks outside. He starts to hallucinate all of the phones ringing and begs them to stop. Finally he gets control of himself and goes to the phone department, and then starts dialing all the phone numbers, starting with the As. He soon realizes the monumental nature of his task. Working on his earlier assumption that the other person is a woman, Walter realizes that she'd go to a beauty salon. He starts calling salons and finally gets hold of the woman. She introduces herself as Genevieve Selsor and Walter tells her to stay where she's at, in a city 900 miles away, until he can drive there.
As Walter drive across the Martian desert, he keeps in contact with Genevieve by cell phone. Desperate for company, he sings her name and imagines what she'll be like. He finally pulls up at the beauty salon, grabs a bouquet of flowers, and goes inside. He finds Genevieve: a morbidly obese woman with her face covered in chocolate. Walter is stunned into silence and Genevieve takes the flowers and wonders if they should kiss or shake hands. Walter quickly offers to shake hands and then has to pry his hand out of her grip. He suggests they go see a movie and Genevieve asks to see a romantic film. Walter balks at the idea and Genevieve invites him to come to a restaurant where she's set up a candlelit dinner for two. Walter starts drinking heavily and Genevieve steps into the next room and then returns... wearing a wedding dress. They share a toast and Genevieve explains that when the exodus was ordered, she decided to stay behind because she had nothing to go back to on Earth. She starts eating and complains about how men always leave her.
Genevieve suggests they go and get milkshakes. As they walk down the street, she takes some perfume from a store and douses herself in it, and then asks Walter for a kiss. He distracts her with the milkshake and suggests she get some rest. When she starts talking about children and looks suggestively at Walter, he finally says that he needs to say one more thing to her. He tells her "Goodbye" and runs to his car. As he drives away, Genevieve screaming after him, Walter throws his cell phone away as it starts to ring... and ring... and ring.