Al Hickey (Bill Cosby) and Frank Boggs (Robert Culp) are tired, broke, alcoholic detectives approached by a lawyer (Lou Frizzell) to find his girlfriend who has gone missing. The 'girlfriend' is actually the only living member of a bank holdup crew that stole $400,000 thousand dollars from a Detroit Bank. When Hickey starts to investigate he finds a murdered lead and Boggs discovers evidence that leads to the fact that the bank robbery from years before has a woman sending thousand-dollar bills to fences as an invitation to buy back the $400,000 in stolen money. The woman, Mary Jane, it seems is married to a leader of a Black Panther-like radical group, and is covering up trails to her by killing off loose ends and also trying to find a buyer for the stolen dough. When the lawyer fires Hickey and Boggs, and the Chief of Detectives Papadakis (Vincent Gardenia) starts to pressure the detectives after dead bodies begin showing up, Hickey and Boggs decide to track down the stolen money for the $25,000 thousand dollar reward. Attempts at tracking down the money and the girl goes wrong time after time and Hickey and Boggs get information from a direct contact in the leftist radical group run by Mr. Leroy (Sil Words) on the possible location for the woman. An established corporation of business-like gangsters run by Mr. Brill (Robert Mandan) are on Mary Jane's trail too and are alternately killing as they discover the thread that leads them closer to the stolen bank loot, and to Hickey and Boggs and their own investigation. The gangsters execute Hickey' wife, momentarily sidelining the duo's efforts but eventually galvanizing their motivations to locate the money and the culprits who have caused so many deaths.