The Road to Hong Kong

Chester suffers amnesia after his do-it-yourself interplanetary flight kit explodes during a scam in Calcutta. The device backfires, injuring him physically and leaving him with memory loss that can only be cured by Tibetan monks.

The scam's failure sets the entire chain of events in motion, as Chester's amnesia drives the journey to Tibet.

The Third Echelon is a shadowy organization that wants to launch a rocket from an underwater pad in Hong Kong to reach the moon first. Their goal is to establish a base on the lunar surface that would give them control over survivors and nuclear capabilities on Earth, allowing them to dominate the post-nuclear world.

Diane's opening briefing reveals that moon-bound transmissions actually originate from Americans, not Soviets, hinting at this secret agenda.

The organization originally planned to use apes for the moon mission, but switched to human astronauts, specifically Chester and Harry, when they realized sending two well-known American figures would generate far greater international prestige and media attention than anonymous primates.

The shift from apes to humans occurs once Chester's memory becomes useful for recalling the rocket formula.

At the airport, Chester accidentally grabs a suitcase meant for a Third Echelon contact. Diane, an agent delivering stolen Russian rocket fuel plans, mistakes Chester for the intended recipient since he has the marked suitcase. This triggers the Third Echelon to pursue Chester and Harry, believing they have the formula.

The mistaken identity establishes Chester as a target even before his memory becomes valuable.

The formula is the secret plans for a revolutionary rocket fuel, stolen from the Russians, that the Third Echelon desperately wants to secure. Chester inadvertently memorizes it while it was planted in his coat, making him a target because he literally carries the valuable intelligence in his mind.

The formula's existence is established early through Diane's mission to deliver it to Third Echelon contacts.

The Tibetan tea leaf given to Chester at the lamasery grants extraordinary memory powers, allowing him to perfectly recall anything he studies. After drinking it, Chester successfully memorizes the Russian rocket formula that Diane had planted in his coat, making his memory literally more valuable than the written document.

The monks' treatment of Chester in Tibet directly enables his memory abilities, which becomes central to the plot.

Harry destroys the formula because he doesn't understand its importance. After Chester memorizes it, Harry thinks the paper is useless and destroys it, not realizing it was the original copy of the stolen Russian rocket fuel plans that the Third Echelon wanted.

Harry's greed and lack of comprehension about the formula's significance leads to the loss of the only physical copy.

Diane learns that the Third Echelon plans to dissect Chester and Harry after the moon mission to study how the memory herb affected their brains. Horrified by this exploitation of the men she recruited, she helps them escape and guides authorities to stop the organization.

Diane's growing attachment to Chester and Harry throughout the story makes her eventual betrayal of the Third Echelon believable.

An agent working for the High Lama substitutes ordinary tea leaves for the stolen Tibetan memory herbs during the journey to Hong Kong. This prevents anyone from reusing the memory-enhancing substance, apparently to keep such powers from being exploited by outside forces.

The substitution occurs specifically as they travel toward Hong Kong, where the Third Echelon's moon launch is imminent.

Chester's memory is fully restored during the lunar mission when the moonlight triggers a回想. The moon landing somehow completes the cure that the Tibetan tea began, confirming that the memory powers can be a dangerous tool in the wrong hands and making Chester's knowledge even more valuable.

The moonlight restoration ties the Tibetan cure directly to the moon mission's purpose.

The film ends with Chester, Harry, and Diane aboard a rocket bound for another planet, believing they'll be isolated. When Chester shouts 'The Italians!', it reveals that Frank Sinatra and Dean Martin have joined them, a whimsical cameo that transforms their grim escape into an absurdly happy finale, matching the movie's whimsical tone.

The surprise cameo subverts the expectation of isolation, turning what seemed like exile into an adventure with famous companions.