During the late 1960s, naïve Oklahoma farm boy Claude Hooper Bukowski arrives in New York City to sightsee for a couple of days before enlisting in the Army and fighting in Vietnam. In Central Park, he notices three stylish women on horseback, who are being taunted by a group of frolicking hippies. Claude makes eye contact with one of the women, Sheila Franklin, and is immediately entranced. Meanwhile, George Berger, the impulsive, charismatic leader of the hippies, and his three friends, Jeannie Ryan, Lafayette “Hud” Johnson and Woof Daschund, rent a horse and attempt to ride alongside the prim socialites. When the rental horse bolts away, Claude comes to the rescue and reins in the animal. He then gallops past Sheila, showing off his rodeo skills, but she and her friends ride off in another direction. Afterward, Berger invites Claude to smoke marijuana and hang out in the park. Claude is amazed to learn that pregnant Jeannie is unconcerned whether the father of her baby is Woof or Hud. The next morning, as Claude prepares to leave the group, Berger finds a photograph of Sheila in the newspaper, announcing her debutante party. He suggests they attend so Claude can meet the girl. The hippies appear at the formal gathering in their Bohemian attire and mingle as if they were invited. At the dinner table, they are asked to leave, but Berger refuses. As Sheila’s father contacts the police, Berger announces to the astonished guests that Claude is in love with Sheila and wanted to see her one more time before leaving for Vietnam. Meanwhile, Sheila, who has been smoking marijuana with her girl friends, is quietly amused and flattered by the intruders. In court, Claude and the hippies are each sentenced to thirty days in jail unless they can pay the $50 fine. Although Claude has enough money to meet his bail, he reluctantly gives the cash to Berger, who promises to collect bail for everyone once he is released. After an unsuccessful attempt to hustle Sheila and her preppy boyfriend, Steve, Berger approaches his parents. Although his father tells him to get a job, his mother takes him aside and gives him $250. Meanwhile, in jail, Woof refuses to let the barber cut his long blonde hair. Upon release, the group joins a large crowd of counterculture tribes and anti-war protestors in Central Park. There, Claude takes the psychedelic drug LSD and hallucinates about his marriage to Sheila in a Hare Krishna wedding ceremony. When he becomes clearheaded and reunites with Berger and the group later that evening, Sheila is with them. She initially appears shy and indifferent, then summons the courage to swim naked with Claude. However, she runs away angry when Berger sneaks off with their clothes. Although Berger is amused by the prank, Claude reminds him that he is leaving the following day for the army and will not have another chance to see Sheila. A draft dodger, Berger cannot understand why Claude is enlisting, but Claude criticizes Berger for his lack of responsibility. Disappointed, Claude walks away from his new friends. The next day, Claude reports to the Army’s induction center and is transferred to a training base in Nevada. Sometime later, he writes to Sheila. When she shares the letter with Berger, he suggests that the friends should drive to Nevada for a visit. After stealing Steve’s car, Berger, Sheila, Woof, Hud, and Jeannie crowd into the vehicle for the cross-country journey. They are also joined by Hud’s fiancée, who is the mother of Hud’s young son, Lafayette, Jr. Unlike the free-spirited hippies, the young mother worries that Hud has fathered Jeannie’s baby. When the group arrives in Nevada, they are immediately turned away from the base by military police. Determined to see their friend, they devise an alternative plan. At a nearby bar, Sheila flirts with a base officer named Fenton and steals his uniform, while Hud confiscates the man’s car. With a new short haircut, Berger dons the uniform, drives to the gate in Fenton’s car, and is waved past security. Locating Claude in one of the barracks, Berger tries to coax his friend into hiding in the trunk and sneaking off base for a few hours. Although Claude is thrilled about the surprise visit and desperate to reunite with Sheila, he says the plan is too risky, since the base is on alert and recruits are subject to frequent head counts. Berger and Claude then agree to switch places, and Claude drives off base disguised as Officer Fenton. While Claude visits Sheila and the group in the desert, his unit is suddenly deployed overseas. Frightened, Berger is forced to march onto a plane bound for Vietnam. Claude panics when he returns to the base and realizes his friend is gone. Sometime later, at a military cemetery in Washington D.C., the friends mourn Berger’s death, and the peace movement gains momentum.