The plot of In the Heat of the Night by John Ball revolves around the murder of Italian-American orchestral conductor which is discovered by Sam Wood, a police officer, on his nightly drive through town. When an African-American man, Virgil Tibbs, passes through town, he is picked up by the police; however, it is discovered that Tibbs is a homicide detective from Pasadena. Despite the racial prejudice of the police chief, Chief Bill Gillespie is persuaded by councilman George Endicott to let Tibbs try to solve the murder case. If he fails, the chief rationalizes, then there will be a scapegoat.
The first suspect, Harvey Oberst, is taken in by Gillespie is proven innocent. As Chief Gillespie realizes that he may not keep his job, he lets Tibbs work freely under his command so he can take credit if the case is solved. The first suspect that Gillespie has brought in is released since he is left-handed, and Virgil determines that the murderer has to be right-handed. Tibbs is hampered in his investigation by Gillespie's and the town council's dislike of a black man's solving the case. Gillespie tries to outdo Tibbs when he becomes suspicious of Sam Wood who has made a sizable deposit into his bank account recently. He also investigates Eric Kaufman, right-hand man of the decease maestro. So, with this interference, Virgil Tibbs has to convince Gillespie that Sam in innocent and refute Delores Purdy's claim that she was raped by Sam.
As the town's patience is about to run out, Virgil Tibbs solicits the aid of a black minister to help him with information from the townspeople; also, he has a critical converstion with the Endicotts as to what they knew about Mantoli. After he intimidates Delores Purdy sufficiently, she admits that Sam is innocent of harming her, and Virgil takes a night ride with the police officer. He has narrowed down the circumstances enough to know who and where the murderer will be. As they sit by the pharmacy, Ralph, the diner-waiter who has gotten Delores into trouble, comes out of the shadows.