MACHINE GUN MCCAIN

Charlie Adamo, the Mafia's recently promoted operations chief on the West Coast of the United States, attempts to muscle in on the newly constructed Royal Casino-Hotel in Las Vegas, demanding its manager Abe Stilberman sell him a 20% stake in the enterprise. When Stilberman refuses, Adamo arranges for convicted bank robber Hank McCain to be released from prison by his son Jack, who poses a plan to rob the casino without telling him of Adamo's involvement. McCain is interested, but he is wary of his son's obvious naivete and suspects more is happening than he's being told. Nonetheless, McCain begins casing the Royal, picking up and marrying an eager young woman named Irene along the way.

Unbeknownst to Adamo, the Royal is owned by the Mafia. His superior, Don Francesco, demands he cease any attempt to buy a stake, and Adamo orders the heist called off immediately. However, McCain is determined to see it through and ignores his son's calls. Eventually, he agrees to meet him in a remote warehouse, where he points out that Jack's two cohorts (working for Adamo) plan to kill them both. McCain manages to kill them instead, but not before his son dies in the crossfire.

McCain carries out his plan, setting off time bombs throughout the casino, detonating a second explosion outside town to distract authorities, and disguising himself as a firefighter to rob the safe while the building is evacuated. The plan goes off without a hitch, but Don Francesco learns of Adamo's involvement through the machinations of his wife. He tortures McCain and Irene's identities out of Adamo before having him killed.

McCain and Irene are now on the run, with the Mafia distributing photographs of the two among their network of informants. With nowhere left to turn, McCain goes to his old lover and partner-in-crime Rosemary Scott. She arranges their safe passage out of the country, but she is found out and captured by Francesco's men. She kills herself before she can be tortured for information.

Irene is spotted by an informant and captured. Francesco's men take her to McCain's awaiting boat, where they kill her. Enraged, McCain blindly fires at his assailants, but he is unceremoniously shot and killed. His and Irene's bodies are quietly disposed.

McCain’s heist succeeds but the Mafia uncovers the plot, leading to Irene’s capture and murder and McCain being fatally shot, with both bodies disposed of quietly.

The ending underscores the merciless grip of organized crime, where ambition and independence are punished without mercy. Even a meticulous plan and seasoned criminal experience can’t outmaneuver the omnipresent Mafia, and loyalty or cleverness offer no protection. The film lands as a cautionary tale about the futility of challenging entrenched criminal power and the tragic cost paid by those who try.