Tsutsumi Kotaro (Nakamura Aoi) is a teenager living in Toyama Prefecture who fails to get into a prestigious high school in Tokyo. Kotaro's mother (Tezuka Satomi), afraid of what others will think, decides to send Kotaro off to distant relatives - the Miyamoto family. In the process, Kotaro must transfer to a high school in Himi City. Next door to the Miyamoto family lives Ichinose Nagisa, who is in the same grade and attends the same high school as Kotaro. In order to help her mother (Hada Michiko), who supports the family alone, Nagisa stops playing for the handball team and even gives up her pursuit of becoming a nurse. For the upcoming school cultural festival, Kotaro and Nagisa happen to partner together to build a planetarium. While Kotaro and Nagisa are looking at the stars, Kotaro recalls his past when he was fascinated by space and hooked on astronomy books. Kotaro then decides on one thing. Meanwhile, Kurita Minako (Kodama Kinuyo) is a classmate of Kotaro. Minako also has a crush on Kotaro. Also, Masaki is the only son in the Miyamoto family. He is Nagisa's first love.