The Mouse on the Moon

Grand Fenwick faces a financial disaster as its wine exports collapse in the market. Mountjoy decides to ask the United States for a loan, ostensibly to fund a Moon race. He believes the Americans will view the request as inexpensive propaganda to promote international co-operation in space, saving the duchy in the process.

The Americans not only grant the loan but send back double the amount as a gift. Mountjoy interprets this windfall as a stroke of lucky propaganda, convinced that Grand Fenwick's space ambitions are timely. The windfall fuels the project and solidifies his plan to stage a launch.

The Soviets respond by delivering an old rocket, hoping to outdo the Americans. The launch broadcast is punctured when its nose cone accidentally smashes a window in Grand Fenwick's Parliament. The incident becomes a symbolic misstep in the hoax-filled plan.

Mountjoy asks Professor Kokintz to arrange a small explosion during the 'launch' to show that the funds have been spent. He hopes to fool observers into believing the project is real and well-funded. Kokintz agrees and begins to orchestrate the deception in secret.

News media commends Grand Fenwick for promoting international co-operation in space. They cite the American funding, Soviet rocket technology, and even a British horology element—the watch Vincent wears—as part of the mission's lore. The coverage helps sell the hoax to a global audience.

Vincent returns after studying in England, bringing a strong sense of fair play and ambition to become an astronaut. Mountjoy is disappointed that Vincent won't be a dutiful heir, but instead a rising rival who wants to fly. The new dynamic sets the stage for the actual flight.

Professor Kokintz reveals that exploding wine, properly treated, can serve as rocket fuel. The discovery provides a plausible rationale for the staged expenditure and the claimed propulsion. Vincent and Kokintz secretly begin preparing the rocket for flight.

Kokintz and Vincent work in secret, planning the launch and improvising with limited resources. They begin modifying the vessel and rehearsing the mission away from prying eyes. The plan hinges on convincing others that the mission is a real, funded voyage.

Maurice Spender, a bumbling British spy, tours the ship and witnesses the 'truth' behind the mission. He reports back to his bosses that the launch is a hoax, adding a layer of international intrigue. His suspicions set up a potential diplomatic headache for Grand Fenwick.

Mountjoy invites the Americans, Soviets, British, and other European dignitaries to witness the launch. The ceremony marks the public face of the project. The rocket lifts off with Kokintz and Vincent aboard, seemingly as a real government-backed flight.

The voyage is supposed to take three weeks to reach the Moon, and Vincent accidentally hits a switch that speeds up the journey. Kokintz and Vincent become the first humans to set foot on the Moon. The arrival disrupts expectations, leaving the later fleets to scramble, with their propaganda plans in disarray.

The Americans and Soviets race to salvage a propaganda edge, nearly entering the wrong ships and then plummeting into the soft lunar dust as they attempt lift-off. They unexpectedly hitch a ride back with Kokintz and Vincent to return home. The whole space-race mood collapses into farce.

The astronauts return to Grand Fenwick during a memorial ceremony, having been out of radio contact for weeks and presumed lost. Diplomats immediately start squabbling about who reached the Moon first. The affair ends up as a public relations satire rather than a serious triumph.

Grand Duchess Gloriana XIII unveils a statue commemorating the successful moon mission. The ceremony provides a celebratory culmination amid the diplomats' squabbling, underscoring the film's satirical tone.