When his partner is killed, tough Irish detective Eddie Ryan vows to avenge the death, whatever the cost. As he begins unraveling clues, his behavior becomes so outrageous that he's obliged to turn in his badge, but the experience only emboldens him. Ryan eventually learns that his partner was caught up in a Puerto Rican gun-running scheme masterminded by a crook named Sweet Willie, who wants to foment revolutionary war.
Badge 373 is a 1973 American neo noir crime thriller film inspired, as was The French Connection, by the life and career of police officer Eddie Egan, here called "Eddie Ryan". The film, which has a screenplay by journalist Pete Hamill, was produced and directed by Howard W. Koch, and stars Robert Duvall as Ryan, with Verna Bloom, Henry Darrow and Eddie Egan himself as a police lieutenant.