Fumihiko Matsumaru, a 26-year-old single salaryman of average appearance, invited a girl to the movies but was stood up. Just as he was about to throw his tickets in the trash, a cute girl appeared and asked him not to waste them. After the movie and dinner, he walked her home, only to discover her apartment was on fire. With nowhere else to go, 20-year-old rookie voice actress Aka Onda moved into Matsumaru's place, and the two began a "more than friends but not yet lovers" relationship under the same roof—facing many obstacles along the way.