In 2006, Mutta Nanba and his brother Hibito witness a UFO heading towards the Moon, sparking their shared dream of becoming astronauts. Years later, Mutta finds himself in a mundane job while Hibito gears up to be Japan's first man on the Moon. When a sudden job loss presents Mutta with a shot at redemption through JAXA, he seizes the opportunity to chase his long-buried Martian aspirations. With self-doubt in tow, Mutta sets off on a daring quest to make good on a childhood pledge made under the stars.