Lou Ford is a 29 year old deputy sheriff in Central City, Texas. It is a small town where everyone knows everyone else. Lou comes across as a boring man. People think he is kind of slow. He has a girlfriend, Amy Stanton, a local schoolteacher. He just seems like a normal guy.
Underneath this exterior is a cunning killer. He thinks he keeps this side hidden from everyone. He meets Joyce Lakeland, a prostitute, and starts a twisted relationship with her. He says that she unlocks the sickness in him. Here we see the start of what is really going on inside Lou's mind. We learn that Lou has had these feelings since he was a child. He sexually abused a young girl when he was little, and his foster brother, Mike, took the blame to save Lou from prison. Mike is released and ends up dying on his construction job. Lou begins to spiral into madness with his quest for revenge for his brother's death. Lou leaves a wake of dead people in his path. His true self emerges and he can't hide from it.
Towards the end, Lou starts trying to blame other people for the way he is. He blames his father at first. The statement he makes "There was plenty wrong with me. Joyce Lakeland was wrong with me" goes to show that he is blaming her now. He blames Joyce, because he said that she called the sickness out in him. He is trying to say that of all the things wrong with him psychologically, his relationship with Joyce is one of the worst. The reader sees that Lou is a sociopath and nothing would have stopped him from doing the things he did; his relationship with Joyce is a symptom of that. Jim Thompson creates a tale of madness and of how the people we think we know hide some kind of darkness inside.