Joe (George Burns), Al (Art Carney), and Willie (Lee Strasberg) are three elderly men sharing a cramped apartment in Astoria, Queens, New York City. With their lives revolving around monthly social security checks, they fill their summer days sitting on a park bench, reading newspapers, feeding pigeons, and warding off rowdy children. This monotonous existence pushes Joe to propose a radical plan in order to inject some excitement into their lives.
After the trio visits the bank to manage their social security checks, Joe suddenly suggests: > "Why not go on a stick-up?" Fueled by boredom, he insists that the risks of bank robbery are minimal—if caught, they'd enjoy free room and board in prison, and their social security checks would continue to accrue. If they succeed, they'd gain some extra cash to enjoy life rather than lingering on their park bench. While Al finds the idea appealing, Willie is more cautious. As plans take shape, Al agrees to explore his nephew Pete's gun collection, and Joe proposes they scout a bank in New York City for the heist.
Al secretly borrows some pistols from Pete's collection—his nephew, who struggles with financial woes while trying to open a furniture store. Convinced the bank robbery might even aid Pete's dire circumstances, Al feels justified in their choice.
The following day, the determined trio journeys into Manhattan and, after some deliberation, decides on the Union Marine Bank as their target. Enjoying hot dogs from a street vendor and engaging in a sidewalk drum performance, they sip the refreshing air of newfound exhilaration. Al is poised to secure the guns later that day, and Joe suggests going through with the heist the very next day.
Donning Groucho Marx-style glasses as disguises, Joe and Willie prepare themselves, while Al sneaks into the basement of Pete's home to acquire the weapons. Once they finalize the bullets that fit the pistols, the trio heads out, taking a bus to a more discreet neighborhood in Queens. They hail an unlicensed cab and pay $30 for transport into Manhattan, asking the driver to wait while they "sign a will."
Entering the bank, Al swiftly holds the security guard at gunpoint while Joe commands the teller to hand over money. The manager underestimates the elderly men, prompting Joe to fire a warning shot, forcing everyone to take cover. After filling their satchel with cash, the three friends dash outside to the waiting cab and make their way back to Queens.
Once home, they discover that their haul exceeds $35,000. Al proposes stashing the money in an old suitcase at Pete’s house. However, tragedy strikes when Willie suffers a heart attack on their regular bench after overhearing news of their crime. Joe wastes no time in making elaborate funeral arrangements.
During the memorial service, Joe and Al decide to give Pete $25,000 from their ill-gotten gains, claiming it as a life insurance payout for Willie. In return, they request $20 a week to aid in their fixed incomes. After the funeral, they impulsively jet off to Las Vegas for a spontaneous vacation, purchasing tickets on a whim.
At a casino hotel that night, they gamble at the craps table. Though unfamiliar with the game, Joe guides Al, and to their astonishment, they win $73,000 by evening's end. Realizing their winnings could make them targets, Joe gets them to cash out and return to New York that night.
Exhausted from their whirlwind adventure, they collapse into bed. Unfortunately, when Joe rises, he finds that Al has passed away. Distressed, he takes the bag of money to Pete, revealing all about the robbery, winnings, and Al's death. In tears, Pete agrees to help conceal the funds in a safety deposit box, vowing to keep the police out of it.
The next day, while preparing for Al's funeral, Joe is unexpectedly arrested by FBI agents. Despite being interrogated, he remains tight-lipped about the money's whereabouts. Later, in prison, Pete warns Joe about the consequences of withholding the cash, but Joe expresses his indifference toward his life sentence. He believes Al and Willie would have wanted him to keep the money, explaining that he had felt imprisoned by their dull lives long before.
He revels in prison life, enjoying regular meals and comfort, and advises Pete to take pleasure in his newfound inheritance. In the film's final scene, as he's escorted back to his cell, Joe flashes a sly grin at Pete, stating: > "Besides... no tin-horn joint like this could ever hold me!"
