As gas station attendants, The Three Stooges show a robber they know how to get the last laugh.

Senator Chalmers is aiming to take down mob boss Pete Ross with the help of testimony from the criminal’s hothead brother Johnny, who is in protective custody in San Francisco under the watch of police lieutenant Frank Bullitt.

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.