"The film begins with the disappearance of Pennsylvania corporate executive Tom Gruneman (briefly seen in the opening sequence) whose family hires a friend - police officer John Klute (Sutherland) - to act as private investigator to look for him. A typewritten obscene letter found in Gruneman's desk leads Klute to his only lead Bree Daniels (Fonda) - a call girl living in New York City to whom the letter was addressed.

The relatively provincial Klute becomes drawn into Bree's seedy world, discovers several of Bree's fellow call girls have been murdered by a homicidal 'john,' and that she herself was nearly killed by the same man - presumably Gruneman. After an uneasy start the two work together to track down the killer.

Along the way the small town cop Klute and cynical city slicker Bree develop an unlikely romance as he becomes protective of her and offers her a kind of genuine affection to which she is completely unaccustomed."