- Directors: Billy Bob Thornton
- Producers: Larry Meistrich, David L Bushell, Brandon Rosser
- Writers: Billy Bob Thornton
- Genres: Drama
- Actors: Billy Bob Thornton, Dwight Yoakam, J T Walsh, John Ritter, Lucas Black, Natalie Canerday
Karl Childers (Thornton) is a mentally challenged man who has been in the custody of the state mental hospital since the age of 12, having killed his mother and her lover.
Although thoroughly “institutionalized”, Karl is deemed fit to be released into a world “too big” for him. Prior to his release, he is interviewed by a local school newspaper reporter to whom he recalls in detail the brutal murder of his mother and her lover with a kaiser blade (noting “some folks call it a sling blade”). Karl claims to have killed the boy for supposedly raping his mother. When he found out his mother was a willing participant, he killed her too.
Having a knack for small engine repair, Karl eventually gets a job at a local lawnmower repair shop. Not long after, he befriends Frank (Lucas Black). Karl shares with Frank some of the details of his past, including the killings. Frank reveals that his father was killed, leaving him & his mother on their own (he later admits that he lied, and that his father committed suicide). Frank introduces Karl to his mother Linda (Natalie Canerday), as well as her gay friend Vaughan (John Ritter). Despite Vaughan’s concerns, Linda allows Karl to move into her garage. This does not sit well with Linda’s abusive boyfriend Doyle (Dwight Yoakam).
Doyle becomes increasingly abusive with Karl and Frank, leading to a drunken outburst and physical confrontation with Frank. Though Linda initially kicks Doyle out of the house, she later reconciles with him. After Doyle confronts Karl and Frank again, Karl begins to realize that he is the only one who can bring about a change and spare Frank and his mother a grim fate. In premeditated fashion, Karl tells Frank to spend that night at Vaughan’s, and asks Vaughan to pick up Linda. Later that evening, Karl returns to Linda’s house. After asking Doyle how to reach the police, he promptly kills him with a lawnmower blade, turns himself in, and is placed back in the state mental hospital.