In 1964, the United Nations (UN) has launched a rocket flight to the Moon. A multi-national group of astronauts in the UN spacecraft land on the Moon, believing themselves to be the first lunar explorers. However, they discover a Union Jack flag on the surface and a note mentioning Katherine Callender, which claims the Moon for Queen Victoria. Attempting to trace Callender, UN authorities find she has died but that her husband Arnold Bedford is still living, and resides in an old people's home. The nursing home staff do not let him watch television reports of the expedition because, according to the matron, it "excites him", and dismiss his claims to have been on the Moon as an insane delusion. The UN representatives question him about the Moon and he tells them his story. The rest of the film, as a flashback, shows what Bedford and Professor Cavor did in the 1890s.