Bender becomes a notorious graffiti artist; when he is caught and arrested, he calls Amy to bail him out. Amy and Kif are arguing when he calls; they're going through a rough patch in their relationship. At the jail, Kif is so upset by Amy's proclivity to flirt with bad boys (including an escaped prisoner who tries to take her hostage) that he breaks up with her. That night the crew toasts Amy getting back in the game. Fry asks if she and Kif are getting divorced. She says no: actually, they were Fon-Fon Ru, so they're not really married. She dismisses Kif's accusation of her being attracted to bad boys as stupid. Bender is rude to her all night, and when she complains, he tells her to shut up. "Don't tell me to shut up!" she says: "You know what happened to the last guy who told me to shut up?" We cut to Amy and Bender in bed together, post-coital.
The next day Amy tells Bender that they can't tell anybody about their relationship, since love between humans and robots is taboo. At work, Hermes is coming down with circusitis, which is turning him into a clown. The Planet Express crew notices lipstick on Bender's face, and gear imprints on Amy's sweatpants... which Bender is wearing. They make excuses, and keep their secret, but that night they are caught kissing by a robot preacher, who denounces them as an abomination. He whips up an angry crowd, but Bender manages to deflect them by yelling: "Look! A single mother! Let's get her!"
The next day, on the planet Tornadus (a world full of tornadoes) Professor Farnsworth has the crew capture a tornado for his collection of pickled weathers for the upcoming county fair. Just before miniaturizing the captured tornado, they see Amy and Bender's clothing inside the tornado. They think their friends have been torn to shreds, but when the tornado is removed, Bender and a half-naked Amy are revealed in an embrace. The Professor is outraged; he is passionately against robosexuality. The rest of the crew isn't bothered. The Professor calls Amy's parents, who drag her home. He also calls the robot preacher, who drags Bender off to a re-programming camp, where they'll be reprogrammed by faith... and some tech-support guys in India. The preacher scoffs at the idea that some robots are hard-wired to be robosexual. Amy's parents try to force her to choose a human mate. Fry arrives to rescue her... uh, "from her robosexual desires," he says, winking at Amy. The two leave together. "My parents may be evil," says Amy, "but at least they're stupid."
Back at the re-programming camp, the preacher makes the robots wrestle with their demons by making out with life-sized, stuffed, human-shaped dummies. The preacher gets turned on by the sight, and then excuses himself. Bender misses Amy, but it turns out that Amy's inside his dummy... as are the rest of the Planet Express crew. They rescue Bender and take him home, where he proposes to Amy. They can get married in Space Massachusetts, but that's not good enough for Bender. He's going to campaign to legalize robosexual marriage. They introduce Proposition Infinity to the ballot.
Despite their campaigning, the movement seems doomed, especially after a fear-mongering commercial subsidized by the Professor. They've got one last hope: a big, televised debate between Bender and the Professor, hosted by the head and neck of George Takei. Bender argues that "our love isn't any different that yours – except it's hotter. 'Cause I'm involved." The Professor says he hates robosexuals because Eunice, a girl he loved when he was much younger, left him for a robot. He further admits that the girls' name wasn't Eunice... it was Unit. Unit 47. She was a robot. He's been taking his broken heart out on robosexuals; he is suddenly ashamed, and has a change of heart: "At the risk of losing this debate, I beg you... support Proposition Infinity!" Voters approve the measure by a wide margin. Amy's thrilled: "Finally, we can have a legal, monogamous marriage like everyone else!" "Woohoo, yeah –MONOGAMOUS!?" says Bender, who is next seen relaxing on the beach with two robot babes. As a brokenhearted Amy curls up in her room, the radio plays her a long-distance dedication from "a squishy green bad boy." Outside her window is Kif in a leather jacket and shades. Amy smiles, and the two ride off into the sunset together on a motorcycle.