The story unfolds in a flashback as Diane explains to American Intelligence that transmissions from passengers snatched from a missile bound for the moon originate with Americans, not Russians. In Calcutta, Chester Babcock and Harry Turner profit by selling a “Do-it-yourself interplanetary flight kit” that backfires, injuring Chester and leaving him with amnesia. An Indian doctor notes that the only plausible cure lies with the monks in a Tibetan lamasery, setting the stage for an unlikely journey.
At the airport, Chester accidentally takes a suitcase marked to reach a contact for a shadowy organization called The Third Echelon. The person who should receive the stolen Russian rocket fuel plans is mistaken for Chester, triggering a chase that drags the two men toward a faraway, mystifying destination. The plot thickens as the agents and the amnesiac man become entangled in a web of espionage, memory, and ambition.
In Tibet, the pair press on toward the lamasary, where the monks cure Chester and introduce a Tibetan tea leaf that grants extraordinary memory powers. The event unfolds with a touch of surreal humor: a giggling lama, played by David Niven, memorizes Lady Chatterley’s Lover in a scene that underscores the strange blend of wisdom and whimsy at the heart of their quest. Yet the true intent behind the memory gift remains murky, and Harry schemes to seize a bottle for his own lucrative ends, even as Chester’s recall grows sharper.
Returning to Calcutta, Chester tests his newfound memory by reciting the rocket formula that was placed in his coat before the amnesia took hold. The revelation is rapid and tense, and when the moment passes, Diane arrives with an offer of $25,000 to meet in Hong Kong. The tension between memory, loyalty, and profit hangs over the trio as they press onward, pursued by the ever-watchful Third Echelon.
On the voyage toward Hong Kong, an agent of the High Lama replaces the Tibetan memory herbs with ordinary tea leaves, creating a misdirection that only deepens the mystery surrounding the mission. The Third Echelon, determined to secure a space race victory, plans to launch from an underwater pad in Hong Kong and claim first rights to the moon, where a base would supposedly secure control over survivors and nuclear capabilities.
With a Russian moon mission imminent, the organization decides to send two human astronauts—Chester and Harry—instead of apes. The mission succeeds, and Chester’s memory is restored in the glow of lunar light, confirming that the memory power can be a dangerous tool in the right hands. Diane’s resolve hardens as she realizes the plans would lead to dissection and exploitation, so she helps the trio slip away, though they are eventually tracked through Hong Kong and recaptured after a chance encounter with Dorothy Lamour at a nightclub.
Chester, Harry, and Diane end up aboard a rocket bound for another planet, convinced they are escaping into isolation. They discover they are not alone when Chester loudly proclaims, “The Italians!” as they are joined by two more famous figures from the era: Frank Sinatra and Dean Martin, turning a grim pursuit into a wildly improbable finale.
