In the year 2025, Carver Kofax is an advertising executive in Los Angeles. His firm tells him to meet with an artist named Rhonda Washington so that they can collaborate on a campaign whose mission is to "make the ugly sexy." Their initial collaboration is successful, and romance flares up between them. Carver's boss is impressed with their work and sends him and Rhonda to Washington D.C. to collaborate further with the client who'd given the firm this assignment. In a room filled with business professionals from all over the world, Carver and Rhonda are shown a revolting image of a protozoa-type creature and told to make it attractive. Instead of working on the assignment, Carver and Rhonda spend the night making love to each other. They show up fifteen minutes late to the next day's meeting but learn that, somehow, they have won the account.

Carver and Rhonda are driven to the Pentagon, where they meet with the President of the United States and Carver's old advertising professor at UCLA, Professor Watanabe. The President reveals that extraterrestrials known as Travelers recently made contact with humanity. One Traveler, dressed as Elvis Presley, descends to present himself to Rhonda and Carver. He expresses that the Travelers will promise to give humans access to their technology if humans will agree to have sex with them. Unfortunately, the Travelers in their current state are too hideous; it will be Rhonda and Carver's job to make them attractive to the human race.

The duo agrees, and they are shipped to upstate New York. They succeed, and soon, the Travelers are allowed onto Earth, where they began having sex with human beings. Rhonda and Carver are paid handsomely and get married. However, their marriage soon simmers when Rhonda has sex with a Traveler and Carver cannot hide his disgust. They continue to live together under the same roof, but their relationship is almost nonexistent. Carver decides to have sex with a Traveler to try it out himself. He finds it infinitely pleasurable.

As the decades pass, Carver notices how few children he sees in the streets. The appeal of Travelers has become so great that human-human sex no longer seems appealing, discouraging reproduction. One day, Carver crosses paths with his old professor, who gives him a USB. The USB reveals that the technology the Travelers gave humans was used to discourage humans from copulating with each other. Carver joins a band of rebels who plan to bomb the central node of Traveler information; they go through with the bombing but fail to destroy the central node. Their plan was hijacked by Rhonda, who hacked Carver's computer and gave him away to the authorities.

Carver receives the death sentence. He is executed but wakes up 50 years later. Although the Travelers did not appreciate his transgression, they do not believe in killing people either, instead just giving them a "time-out." Carver reaches out to Rhonda but finds himself too disgusted with what she's become to continue their relationship. There are very few humans left and no children. In his dismay, Carver travels to the Elvis-lookalike Traveler, who expresses that the Travelers have plans in store for when the population nears extinction. In the meantime, the Traveler asks Carver if he'd like to have sex. Carver agrees, figuring, "Why not?"