When white woman Nancy Poteet (Evans) is sexually assaulted and beaten by an unknown man in a small town in the Deep South, the Ku Klux Klan, assuming the man is black, begins a campaign of terror against black people. Sheriff Track Bascomb (Marvin) tries to find the guilty party in the rape and calm down the racial tensions while seeking the involvement of Breck Stancill (Burton), a local landowner who helps the African-American community.
Meanwhile, Garth (Simpson) barely escapes with his life after an ambush by the KKK, but a friend of his is killed, after which Garth begins a vigilante set to take out members of the Klan.
This film features examples of:
- Corrupt Hick: Sheriff Bascomb's deputy, Butt Cutt Cates, who is in league with the Klan himself.
- Deep South: The film is set in the deep south and tackles racism and members of the KKK.
- Excuse Plot: Nancy's rape is only used as an excuse to ignite the film's conflict between the KKK and the protagonists, and isn't brought up once the conflict is in full gear. Even Nancy herself seems to forget it once she befriends Breck.
- The Faceless: The face of Nancy's attacker (and in fact, most of his body) is never seen. The one clear shot of any part of him is a freeze-frame shot of his rather dark arm before attacking, leaving it ambiguous if it is because the man is black or because it was dark when the attack happened.
- Groin Attack: It is mentioned that the Klan's victims get castrated.
- Karma Houdini: Whoever was responsible for Nancy's rape is never shown to be brought to justice.
- The Klan: Featured prominently, as the title implies.
- Politically Incorrect Villain: The white supremacist villains.
- Rape Discretion Shot: The film demurely cuts away from the unseen man raping Nancy. Horrifically averted when Loretta is raped by Cates, which is graphically shown.
- Scary Black Man: Garth becomes one when he decides to take out members of the Klan after barely escaping an encounter with them.
- The Sheriff: Sheriff Track Bascomb, who tries to resolve the film's conflict.
- Southern Gothic: While nothing supernatural is going on, the film has such a heavy and oppressive atmosphere that at times it borders on becoming a southern gothic.
- Town with a Dark Secret: Black people are getting murdered by the Klan and half the townspeople are in on it.
- Vigilante Man: Garth starts taking out members of the Klan one by one after he barely escapes an encounter with them that ends with one of his friends killed.
- Villain with Good Publicity: The Klan appears to be this among the white citizens of the town, to the point that the Mayor is invited to one of their reunions despite not being a member, and despite making a point that non-whites are considered a part of society, still states his belief that the Klan are somehow doing a service to the community.
- Would Hit a Girl: Deputy Cates beats up and rapes Loretta.