Once upon a time there were two brothers, Hibito and Mutta. Hibito, the littler brother, had been blessed with good luck since the day he was born. Mutta, the elder, had always had bad luck. One day, looking up at the night sky, the two brothers saw a UFO. This experience made them both promise to become astronauts. In the year 2025, Hibito has kept his promise and is an astronaut who is part of the first wave of people to live for an extended period of time on the moon. Meanwhile, his older brother Mutta has been fired from his job and is unemployed, but a message from his brother makes him decide to start being an astronaut again. Unaware of his own talent, elder brother Mutta chases his dreams to get back in front of his younger brother. 32-year-old Mutta will attempt the astronaut candidate examinations to follow his brother Hibito to the moon believing the words "The older brother should always be ahead of the younger one..." (AKA: Space Brothers)