 Philadelphia police lieutenant Virgil Tibbs and his wife Althea have returned to Sparta to attend the funeral of Virgil s mother. While in town and unknown to Chief Bill Gillespie, Virgil is offered the position of Chief of Detectives. At the same time, a white girl is found murdered in the Bottoms, which allows Virgil the opportunity to begin work. The police force is rife with racism and devoid of proper police procedures. An African-American man, Willie Jones, is brought in on flimsy evidence. Before Virgil can investigate, Jones is found hanged in his cell. Gillespie and Tibbs are at complete loggerheads over how to proceed with the investigation and institute measures to clean up the department.