Snafu writes to Sally that he is going to the South Pacific. The letter is censored and he unsuccessfully tries to mail an uncensored letter. On a Pacific island he dreams that he was successful but that the Japanese got the information and set a trap. He awakens and realizes the danger of revealing information.

The film gives a portrait of mental health treatment during the 50s, which was the heyday of treating mental patients in big institutions.

Two escaped convicts are found hiding in a rocket ship built by a renegade inventor, who forces them to become the crew for a trip to the Moon. Also on board, as inadvertent stowaways, are his assistant and his secretary; and none of them are aware that the inventor is actually a Lunarian explorer sent to Earth by the dying Lunar civilization.