Ryuhei Agawa has had a crush on his neighbor Tamaki Musashibara ever since he was young. However, their ten-year age difference seemed impossible to overcome, as Tamaki always treated Ryuhei as a younger brother rather than a potential romantic interest. Ryuhei is about to give up on his long-held unrequited love, but when Tamotsu Kinugasa enters the picture and catches Tamaki's eye, Ryuhei's competitive spirit rears its head at the sign of a rival. He decides to pursue his attraction for Tamaki in earnest, hoping that she might finally see him as a man. Will Ryuhei finally manage to win Tamaki's heart, or is there no chance for him?