Sugiyama and Sasano attended the same middle school. During their first year in high school, Sasano fell in love with Koga whom he met in high school. In order to help further their slow-moving relationship, Sugiyama and Koga's childhood friend, Hibiya, were watching over the two. Also with the help of the people around them, Sasano and Koga officially became lovers. Following the happiness of the two, Sugiyama and Hibiya began to deepen their relationship from friendship little by little. However, because it was something trivial, they are still under the impression of "being friends". Meanwhile, a year passes and a new encounter comes...