Gator McKlusky is serving his last year in an Arkansas prison for "bootlegging” homemade liquor when his cousin Louella informs him that his younger brother Donnie, an idealistic college student and civil rights activist, has been murdered by being drowned in a lake. Learning that crooked, bigoted sheriff Connors is responsible, a desperate Gator escapes from prison, only to be caught by warden Sims. Determined to bring Connors to justice, Gator agrees to cooperate with U.S. Treasury agents in exchange for an immediate release. After agreeing to collect evidence against Connors, whose dictator-like control over the dry Bogan County includes taking bribes from moonshiners, Gator is given a “souped-up” car to go undercover running liquor. When he tells his parents about his plan to catch Connors, Pa, his father, once a bootlegger himself, is furious that Gator has become a government “stool pigeon,” while his mother despairs that her remaining son will more than likely be killed. The next day, Gator offers Dude Watson, a speedway racer and liquor runner, immunity from prosecution if he aids Gator in collecting evidence against the sheriff, but Dude refuses, knowing Connors would kill him if he were caught. Gator tries again to pressure Dude at his mechanic’s shop. When Dude tries to drive Gator off his property with his shotgun, Gator easily overpowers him and finally convinces Dude to introduce him to liquor runner Roy Boone. Because of Gator’s easygoing attitude and impressive car, Roy hires him as a blocker, a driver who can intervene during police chases. On their first run, police spot Roy, but Gator diverts them into following him through a lumberyard and onto dirt roads. Finally Gator jumps his car onto a sand barge crossing the river, foiling the dumbfounded police. Hoping to get access to Connors’ office to collect evidence, Gator takes out Martha, the sheriff’s middle-aged secretary, but after his goodnight kisses turn abruptly passionate, Martha rebuffs him, surmising that Gator wants some kind of favor. Days later, Roy takes Gator to the main distillery, a backwoods operation that produces 3,000 gallons of homemade whiskey each month. As jugs of whiskey are loaded in Roy’s car, distillery owner Big Bear threatens Gator, whom he suspects of being an informant, with a knife, but Gator charms his way out of the predicament. After making several runs, Roy, his girl friend Lou and Gator go to a diner, where Gator talks to college students, hoping to learn more about Donnie, but Roy dismisses the “draft dodging, pot smoking” kids and Lou admonishes Gator, believing he is just trying to sleep with the teenage girls. The next morning at Roy’s lake house, the flirtatious Lou brings breakfast to the dock where Gator is skinny-dipping. While Roy sleeps, Lou seductively spoon-feeds Gator, who tells her about his prison time after which Lou joins him in the lake for sex. Meanwhile, Connors, having learned from state authorities that Dude is a stool pigeon, laments that the federal government is being taken over by Communists, who, he believes, are turning his own people against him. Meanwhile, when treasury agents arrive at Dude’s shop to get information, Gator, realizing that Connors might learn of their visit, orders them to leave. During a return trip to the distillery, Gator sneaks into the house and takes notes from Big Bear’s books, feigning that he is flirting with Big Bear’s girl friend to divert attention. While making a delivery to a black nightclub, the bartender’s fond memories of Pa McKlusky’s moonshine business shames Gator into throwing his evidence log in a trash can fire. Meanwhile, Connors and his men threaten to rape Dude’s girl friend Maggie unless she tells them where they can find Dude. Maggie sends them to Dude’s parents’ farm, where Connors slams Dude’s father’s hand in the door until the old man tells them Dude is a friend’s house. As soon as Gator, Lou and Roy arrive at there to meet Dude, Big Bear, who has the police on his payroll, and two policemen attack, shooting Dude and handcuffing Gator and Lou, while Roy flees unharmed. Awaiting Connors’ arrival, Big Bear takes Lou and Gator into the house, where Gator gulps moonshine, feigning drunkenness. His tantalizing claims that Lou has tattoos on her belly prompt the three men to see for themselves. While Lou fights them off, Gator grabs Big Bear’s shotgun and hits Big Bear with it, then shoots one of the policemen and knocks the other out with a bottle. As Lou and Gator flee, Big Bear shoots Gator, forcing Lou to drag the barely conscious man into the car. Gator wakes up in a home for unwed mothers surrounded by a dozen pregnant women and nun Linda Fay, who hacksaws off his handcuffs. While hiding there, Gator learns from Donnie’s teenage friend Jenny that Donnie had decided that the students should protest in Bogan County, the most corrupt county in Arkansas. When Donnie demanded a search warrant before allowing police to disrupt a sit-in and then called the sheriff a fascist pig who robbed the public, Connors took him away. Within hours, Donnie was dead. Gator, unable to understand his brother’s commitment to justice, laments that Donnie, who was the only one in the family who had ever gone to college, lost his life for no real reason. Just then Connors arrives, prompting Gator, who is forced to drive one-handed because of his wounds, to back his car through the yard and flee. Connors and deputy Junior pursue him on a dirt road into a cornfield and then into a quarry, where they lose Connors. Soon after, two police cars are in pursuit, but Gator outmaneuvers the drivers, causing them to crash. Connors, who has extricated himself from the quarry, chases Gator, who leads the sheriff over an embankment into a pond, drowning him. Days later, while attending the town parade in Connors’ honor with Lou, Gator is satisfied that justice has been served without causing more harm to the good people of Bogan County, including the moonshiners.