Billy is the “king” of a traveling Renaissance fair troupe that specializes in knights jousting on motorcycles, and adheres to a code of behavior based on King Arthur and his knights. As the fair opens in a small town, a local girl, Julie, is almost run over by a knight, Alan, who offers her a motorcycle ride. Though the sheriff has issued a permit for the fair, two corrupt police officers demand a pay-off to leave the troupe alone. The black knight, Morgan, and the “friar,” Tuck, want to pay, but Billy refuses and takes his place on the throne by his queen, Linet. The tournament begins and the knights joust one on one with lances. Morgan’s round ends in a tie, and the rematch allows for a change of weapons. Morgan chooses a mace and knocks his opponent down. Although wounded in a previous tournament, Billy fights Morgan and is knocked off his bike by the mace. The other knights ride in to rescue their king before Morgan can demand Billy’s crown, and Alan is victorious over the black knight. In Billy’s tent, his wounds are tended by Merlin, the group’s wizard and doctor, and Billy confides that he had another recurring dream of a black bird. Later, a boy, also named Billy, asks the king to autograph his picture in Cycle Rider magazine. Billy was unaware of the article and refuses to sign, claiming it does not reflect his group’s values. The fair includes an opportunity for attendees to joust with the knights, but several locals race onto the grounds, steal weaponry, and speed away. The knights give chase and retrieve the weapons, while forcing the errant motorcyclists off their bikes. That night, Billy and Linet argue. Billy does not want to compromise his ideals, but she believes they must waver in their code because the group needs more money to survive. As the troupe sits around a campfire, Morgan admits that he only recently became interested in the Arthurian legend, and Pippin, the group’s emcee, laughs that Morgan had not realized that his namesake, Morgan Le Fey, was actually a woman. Morgan claims that Pippin, himself, is truly a woman, and Angie, Morgan’s girl friend and the group’s mechanic, questions if Pippin is homosexual. Pippin admits he is not sure, but a female knight named Rocky proudly declares she is a lesbian. The two local officers arrive to harass the group and Tuck, intoxicated, drives away in his truck, parking by the bushes where Alan and Julie are making love. The police search Bagman’s trailer, discover marijuana, and want a bribe, but Billy refuses and insists on going with Bagman to jail to witness further police corruption. Although he orders the troupe to wait for his return, Linet conducts everyone to their next location, asking Merlin to wait for Billy and Bagman. In jail, Billy watches from another cell as the officers beat Bagman. Julie and Alan locate the sheriff, who orders the police to release the prisoners, and Billy warns the lead officer that he will return for vengeance. Meanwhile, Angie, Pippin, and Tuck encounter Steve, the group’s lawyer, on the road. He has set up the paperwork at their next site, and is returning to help Billy. When Billy learns the troupe has already moved on, he is furious, but Merlin calms him. Now at home, Julie packs to leave with Alan, and they discover that her mother was beaten by Julie’s abusive father. The next day, while promoting themselves in town, several troupe members meet television producer, Sheila, a photographer named Judy Rawls, and Joe, a promoter with Silver Bullet Enterprises, who are interested in the troupe, and ask to speak with Billy. Upon learning he has not arrived, Sheila turns her attention to Morgan, who assures her that Billy is not the troupe’s only star. On the road, Steve meets Merlin, Billy, and Bagman. As they camp, Steve mentions the promoters’ ability to provide a bigger circuit and more money. Billy refuses to join the “money world,” insisting that he must fight for the ideals of the code. Later, Billy borrows Steve’s motorcycle, and arrives at the fairgrounds as Sheila meets with his troupe. Billy is angry that they are having a council meeting without everyone present. Sheila tells Joe not to worry; Morgan is attractive and can get a group of knights to leave with him. In their tent, Linet tells Billy that she took a chance and followed him, but is uncertain if he is the reason she stays. Outside, Morgan informs the other knights that he deserves to be king and will leave with Joe after the tournament. Angie insists Morgan did not win the crown and refuses to leave with him, betting that he will return within two weeks. Another knight, Bors, feels the troupe is finished and informs Alan that he might leave, too. At the joust, the fights are more vicious than usual and the knights do not wait for Billy’s signal to begin. When someone switches the music from trumpets to rock music, Billy goes to the sound truck to change it. While he is inside, a motorcycle flies free, and misses an infant, but crashes into the baby’s mother. As the woman is taken to a hospital, local motorcyclists rush into the arena to challenge the knights. Pippin tries to explain the competition is over due to the accident, but the bikers ignore him. As the troupe’s knights race into the arena and dispatch the local riders, a male fair worker named Punch asks Pippin to be his lover and Pippin accepts. Billy steps outside, sees an Indian with a black bird on his armor, and feels this is the challenger he has been dreaming about. Knowing Billy is hurt, Alan attempts to stop him, but Billy fights back, repeatedly knocking Alan off his motorcycle until he yields. Billy faces the Indian in a wild battle. Billy wins, but is injured and collapses. Afterward, Morgan and several knights depart, and Alan leaves with Julie and Bors. The Indian remains with the troupe at the campsite while Billy heals and they wait for the defectors to return. At Sheila’s home, Tuck romances Judy, while Morgan has sex with Sheila, and then learns her rich boyfriend is returning soon. Joe has no use for Tuck, but orders new outfits and motorcycles for Morgan and his men, and stages a Las Vegas, Nevada, photo shoot where Morgan models a metallic bathing suit. While visiting friends, Alan ponders his lifestyle, then returns Julie to her home and leaves with Bors. In Las Vegas, Morgan and Tuck return to the knights’ hotel room to find the men are drunk and fighting. Outside, Alan and Bors confront Morgan, insisting that he cannot break off from the troupe and there can only be one king. Alan and Bors ride back to camp, followed by Morgan and the other knights on their new motorcycles, and Tuck and Judy in his truck. The troupe is excited to see them and Alan promises to fight for the king again, if Billy will let him. Joe confronts Morgan about his contract and is rebuffed, but stays to watch the knights hold a private tournament. After a series of battles, Morgan defeats Alan to win Billy’s crown. As Morgan crowns his queen, Angie, Linet embraces Billy, then steps off the throne into Alan’s arms. Billy says goodbye, then drives off with the Indian. He fulfills his promise to fight the corrupt policeman, and finds young Billy, giving him a sword instead of an autograph. Later, as Billy, still weak from his injuries, imagines he is a knight on a steed, he is hit by a truck. The troupe gathers for Billy’s funeral, and a black bird watches them ride away, led by King Morgan.