Kansas City, 1933 – A time when Prohibition and organized crime dominate the city streets. The most feared crime boss is Leon Coll, played by Tony Lo Bianco, but he faces a fierce rivalry from Primo Pitt, portrayed by Rip Torn, who is intent on usurping Coll's power. One fateful night at a café, Police Lieutenant Speer (Clint Eastwood) crosses paths with his former partner turned private investigator, Mike Murphy (Burt Reynolds). Their reunion escalates into a fight with two troublemakers, prompting Speer to investigate some dubious activities rumored to be linked to Murphy’s agency.
The following day, Murphy's secretary Addy (Jane Alexander), who has been a point of contention between Murphy and Speer, informs him that the men he fought weren't just thugs; they were repo agents. Meanwhile, Murphy’s partner Dehl Swift (Richard Roundtree) arrives, flaunting his newfound wealth, arousing Murphy's suspicions about Dehl's integrity.
Dehl soon finds himself at a nightclub where his girlfriend Ginny Lee (Irene Cara) performs, and hands over $25,000 to Coll's corrupt bookkeeper on behalf of Primo Pitt. Pitt's plan is to seize Coll's accounts and gather evidence to take him down. As Dehl concocts a scheme to double-cross Pitt, Ginny expresses her concern about him getting entangled in such muddy waters.
During a boxing match, while on a date with Addy, Speer observes Dehl meeting with Coll and learns that Dehl just alerted Coll about a betrayal by his bookkeeper. Later that night, Speer pursues Dehl back to his place only to discover that Ginny has been captured by Pitt's men. In a tense atmosphere, Ginny attempts to escape but unfortunately, Dehl loses his life in the process. Speer takes down one of the henchmen but Pitt remains elusive and goes undetected.
At the morgue, Speer briefs Murphy on the ghastly events surrounding Dehl, and shortly thereafter, Murphy is confronted by Coll's men demanding the return of the stolen books. Adding to the tension, Pitt later threatens Murphy by revealing that he has taken Caroline (Madeline Kahn), Murphy's girlfriend, hostage to coerce him into handing over the books.
As the investigation deepens, Speer discovers that the bullet extracted from Dehl's corpse corresponds with one from Pitt's firearm. Desperate for justice, he seeks Ginny's location so she can serve as a crucial witness. In a clandestine meeting, Murphy learns that Dehl stashed the significant financial papers in a boxing gym locker. However, as Ginny attempts to reveal the location, she meets with a terrible accident.
Now in possession of the boxes, Murphy devises a plan to rescue Caroline, but is soon caught in a violent showdown between Pitt's and Coll's men. As chaos ensues, Speer takes charge and joins Murphy in confronting Pitt to negotiate Caroline's return. However, Pitt reveals that Caroline is hidden elsewhere, leading to a frantic battle where explosives come into play. The stakes rise, and in the midst of the gunfire, Speer manages to eliminate Pitt.
With the clock ticking, Speer and Murphy extract the location of Caroline from a remaining thug – a brothel. But complications arise as Addy is abducted by Coll’s crew at her apartment. In a daring move, Speer and Murphy storm the brothel, overpower Pitt’s men, and successfully rescue Caroline. However, as they attempt to escape, chaos reigns when Coll shows up, demanding the papers. In a dramatic turn of events, Murphy hands the case containing the books, alongside explosives, to Coll. As Coll and his men make their exit, their vehicle explodes, culminating in a spectacular climax.
In the aftermath of the turmoil, Ginny takes to the stage once again at the club, while Murphy enjoys a night out with Caroline, and Speer begins dating Addy. Yet, old rivalries simmer just below the surface, leading to an explosive confrontation between Murphy and Speer, closing the film with charged tension and unresolved conflicts.
