Kansas City Confidential

Mr. Big selects three fugitives—Peter Harris, Boyd Kane, and Tony Romano—each with a motive to flee the United States. He interviews them wearing a mask so they cannot identify him. He then outlines a plan to rob the armored car with the flower truck as cover.

A duplicate flower delivery truck is used to approach the bank pickup. The crooks wear masks and subdue the armored car crew, seizing the money and escaping. Mr. Big gives each man a torn King playing card to serve as a future identifier if things go wrong. The gang heads toward Mexico with the loot.

Police arrest Rolfe and pressure him for a confession, but his alibi holds up. The real robbery vehicle is found, clearing his name. Rolfe loses his job and resolves to find the criminals and clear his reputation.

Rolfe tails Harris to Tijuana and traps him into revealing the gang's meeting place. At the airport, Harris is shot by police. Rolfe realizes he can impersonate Harris and retrieves Harris's mask and torn card from his luggage.

In Borados, Rolfe meets Kane and Romano, and Mr. Big is secretly present as well. The others do not yet know who the real mastermind is. The stage is set for a sophisticated trap.

Tim Foster is revealed to be Mr. Big, a former Kansas City police officer. He explains to Andrews that his plan is to trap the criminals, claim the reward, and possibly reclaim his job. He insists he never intended for the money to be split.

Helen, Foster's daughter, arrives and says the mayor has agreed to look into the scandal. She reveals she has met Rolfe and admires him. Foster wrestles with his desire to return to power and his daughter's disapproval.

Rolfe uses a poker game as a pretext to show the torn card and test the others. Kane and Romano react with suspicion, but Foster pretends to stay neutral. Later, Romano catches Rolfe in his room and forces him to cooperate while the money is still in play. The fragile alliance begins to crack.

The next day Kane and Romano ambush Rolfe and beat him; Kane suspects Rolfe is Harris because he was in prison with him. Helen intervenes, and Rolfe uses quick thinking to keep them at bay and buy time while their suspicions simmer.

Foster, still posing as Mr. Big, writes individual notes to Rolfe, Kane, and Romano to meet him on his boat. Kane and Romano try to ambush Rolfe on the way, but Rolfe outsmarts them and insists on Harris's share. The trio is driven to the boat by Foster, who pretends to be going out fishing. They still do not know he is Mr. Big.

On board, Rolfe escapes and comes across the money that Foster had made easy to spot. Romano confronts him with a gun; to buy time, Rolfe shows him the money. Kane is killed by Romano, and Foster's true role becomes evident as Rolfe deduces he is Mr. Big. In the ensuing gunfight, Romano is killed and Foster is mortally wounded.

With his dying breath, Foster tells Rolfe that Helen must not learn the truth and informs Andrews that Rolfe was his source and deserves the $300,000 reward for recovering the stolen money. Rolfe is left to confront the consequences of the deception and the unresolved romance with Helen. The case closes with Rolfe standing as the man who uncovered the scheme and claimed the reward.