To the outside world, Hanabi Yasuraoka and Mugi Awaya are the perfect couple. But in reality, they just share the same secret pain: they are both in love with other people they cannot be with. Hanabi has loved her childhood friend and neighbor Narumi Kanai for as long as she can , so she is elated to discover that he is her new homeroom teacher. However, Narumi is soon noticed by the music teacher, Akane Minagawa, and a relationship begins to blossom between them, much to Hanabi's dismay. Mugi was tutored by Akane in middle school, and has been in love with her since then. Through a chance meeting in the hallway, he encounters Hanabi. As these two lonely souls spend more time together, they decide to use each other as a substitute for the one they truly love, sharing physical intimacy with one another in order to stave off their loneliness. [Written by MAL Rewrite]