The "nameless" San Francisco detective and his partner Eberhardt are trying to prove that their client Thomas Lujack did not mow down his business partner with his car. Although he suspects his client's guilt early on, the 58-year-old gumshoe spends three weeks looking for flaws in the testimony of the hit-and-run's sole witness. Then Lujack is found murdered, the witness disappears, and the detective, instead of being asked to step up his investigation, is discharged by the victim's brother Coleman. In full moral outrage, the veteran detective bulldogs his way through the case, uncovering evidence about the brothers' employment of illegal immigrants.