Vietnam veteran Jack Dunne is arrested for interfering with a U.S. Army recruiter in midtown Manhattan, New York City, and taken to a ward at the Veterans Administration Hospital, where patients welcome him back for the third time. Dr. Ellas admonishes Jack for abandoning his job, but Jack says he is interested only in going to Eureka, California, to start a worm farm with three men from his unit in Vietnam. With the help of an orderly, Jack escapes again with $1,000 his fellow patients invest in his worm farm. Jack buys a new pair of shoes to replace his hospital slippers, and stops at a sports shop to buy enough dirt and worms to fill the shoe box. At Port Authority bus terminal, Jack tells the ticket agent he wants to go to Sedalia, Missouri; Albuquerque, New Mexico; and Eureka, California; but since he refuses to spend any of the $1,000, he has enough money only to get him to Sedalia, with $22 left over. To evade the attention of Port Authority policemen, Jack attaches himself to a young woman, Carol Bell, who wants nothing to do with him, but after he buys the last ticket on the next bus to the Midwest, Jack bribes the ticket agent into selling Carol another ticket. He gives Carol the last remaining seat and crams himself into the back of the bus. During a quick stop in Newark, New Jersey, Carol notices that Jack hides when he sees several policemen. Later, Jack borrows Carol’s red nail polish and writes “Eureka” on the top of his box of worms. During a stop in Pennsylvania to replace a flat tire, Jack digs for worms alongside the road, which prompts Carol to demand that Jack tell others on the bus that she does not know him. Furthermore, she is marrying her fiancé on Saturday in New York City. At the next stop, Carol calls her fiancé to tell him she is in Ohio because she needs to be alone for a few days. Jack calls his friend, Kenny Boyd, in Sedalia to pick him up at the station. At a café counter during a meal, Jack tells Carol that he, Kenny, Adcox, and Larry Munro talked about starting a worm farm when they were in Vietnam. When Jack pulls a worm out of his box, Carol and the waitress panic and he accidentally tosses the worm onto the bus driver's plate. A fight breaks out, so Jack runs from the café with his box, and the police force Carol to pay $300 for damages before they allow her back on the bus. When Carol arrives in Sedalia, she gets off with Jack’s seabag and waits for him, so she can get back her $300, but when Jack arrives in the back of a truck, he tells her his $1,000 bankroll belongs to his investors and he needs their permission before he can pay her. Besides, he does not want her to return to New York. Kenny picks up Jack and Carol in his Camarro and takes them to his run-down farm, where he raises rabbits whose droppings will feed the worms, but Jack becomes angry when he sees only a single cage with three rabbits. Kenny tells Carol he can pay her the $300 Jack owes her if he wins an auto race on Sunday. That night, as Jack and Kenny fire an M-16 rifle at the stars, Jack realizes Kenny is more psychologically damaged than he is. At the race, Kenny wilts when other drivers taunt him, so Jack drives the Camarro and takes third place, which awards no money. Back at the farm, after Kenny, Jack and Carol get drunk on beer, Jack grabs a hammer and starts nailing rabbit cages together. When it is time to leave for Albuquerque to see Adcox, Kenny gives Jack the keys to the Camarro and says he will take a bus and meet them later in Eureka. At a cheap motel, Jack and Carol negotiate how they will spend the night together. Jack confides that the war made him crazy, and he has not been with a woman for a long time. As they kiss, Carol tells him he needs to relax, but Jack becomes anxious and takes a walk by himself. While standing outside, looking at the lights of a nearby bar, two thugs knock Jack out and steal his money. Jack regains consciousness, stumbles back to the motel room to tell Carol what happened, then goes to the bar, where several tough-looking men drink and play pool. He grabs the bartender and demands the return of his money or else he will smash the man’s nose into his brain. As the bartender returns the $1,000, the other men attack, and Jack fends them off until Carol crashes through the front wall in the Camarro and rescues him. In Albuquerque, Jack sleeps as Carol pulls up to Adcox’s address, gets out, and knocks on the door. Adcox’s wife, Jane, tells Carol that she has no idea where her husband is or when he will return. “He drifts,” Jane says. Carol uses Jane’s phone to call her fiancé and tell him she will not be back for the wedding that day. Later, on the way to California, a highway patrolman pulls Carol over because the Camarro's motor is steaming and the windshield is cracked from her barroom crash. When a check of Jack and Carol’s identifications shows that both of them are “clean,” the policeman guides her to a nearby garage. Jack wakes up and wants to return to Albuquerque, but the car’s engine is ruined and he is forced to hitchhike. When a motorist at the garage offers Carol a lift toward California, she talks him into picking up Jack along the road and then convinces Jack that there is no point in returning to New Mexico. They hitchhike to Eureka and arrive at the Munro address, but Larry’s parents tell Jack their son never came home from Vietnam and they are outraged that he is trying to put something over on them. As they order Jack and Carol out of the house, Jack tells them Larry saved his life during a helicopter evacuation and he does not believe that he is dead. As Jack runs through the streets, he relives a firefight in Vietnam and sees Larry lying in the Medi-Vac helicopter with half his face blown away, a scene that he had blocked out of his mind. Carol finds Jack in a field, begs him not to leave her, and says he does not need Larry and the others; he needs only himself, and she will be there for him, too.