Astronaut Capt. Richmond Talbot inadvertently volunteers to make the first manned flight around the moon. He is ordered to keep the upcoming moon flight a secret, even from his family. Due to the secrecy of the mission, he is put under the watchful protection of various security agencies. Despite all the precautions, Talbot is approached by Lyrae, a beautiful, mysterious “foreign” girl who seems to know all about the astronaut's mission and warns him about possible defects in his spacecraft. Comedy ensues when the various agencies assume she is a foreign spy.