In the lively backdrop of Rio de Janeiro, a wealthy man, Henry Holland (Alec Guinness), finds himself recounting a thrilling chapter of his life to a guest. He reflects on how his previous mundane days as a bank clerk in London evolved into an exhilarating escapade. After twenty years of monotony overseeing gold bullion deliveries, Holland becomes increasingly restless and devises a plan to escape his dull routine while exploiting the value of the precious metal.
The turning point comes with the arrival of Alfred Pendlebury (Alfie Bass), an imaginative artist residing at Holland's boarding house. It soon emerges that Pendlebury owns a foundry known for creating distinctive gifts, many of which are sent to Paris. Seeing an opportunity, Holland shares his idea with the eager artist, who is quick to support him.
As Holland faces a departmental transfer, the duo springs into action, enlisting the help of petty criminals Lackery Wood and Shorty Fisher. On the day of their audacious heist, the two criminals hijack the gold bullion van, cunningly swapping its valuable load with items transported in one of Pendlebury's work vans. Holland then assumes the role of an innocent bystander, garnering praise for his swift alerting of the authorities.
While their partners ship the melted gold, recast into Eiffel Tower paperweights for foreign markets, Holland concocts a web of misleading information to misdirect Inspector Farrow’s investigation. Although Wood and Fisher are hesitant to travel to Paris to claim their share, they trust Holland and Pendlebury with the task of distributing their rewards.
The celebration of their triumph quickly takes a chaotic turn as they realize they must reclaim the gold sent to Paris. Their adventure leads them to the iconic Eiffel Tower, where they discover that one box of their gold paperweights has been compromised, and six of them have ended up in the hands of a group of unwitting English schoolgirls. The ensuing chase for the mischievous girls spirals into a comical pursuit as they strive to recover their precious loot.
In the mayhem, Holland and Pendlebury successfully recover five paperweights but find themselves in a bind for the last one. Their quest intensifies upon learning that the final paperweight has been gifted to a policeman at an exhibition illustrating police history at Hendon Police College. As Inspector Farrow closes in on the truth, their anxiety amplifies.
With their ruse unveiled, Holland and Pendlebury hastily flee in a stolen police vehicle, triggering a wild chase through London. To further complicate their predicament, Holland uses the police radio to disseminate false information, aiming to mislead their pursuers. Their escapade takes a turn for the worse when they unknowingly offer a lift to an officer, resulting in their capture.
As Pendlebury gets caught, Holland makes a narrow escape with the remaining six golden paperweights, securing his financial future. However, back in Rio, the visitor has keenly listened to the entire saga, and it soon becomes apparent that the stolen money has vanished. As they part ways, it is unveiled that Holland is, in fact, handcuffed to his companion – a disheartening indication that his criminal misadventures have ultimately ensnared him.
