Although he knows little about ephemeral teenage romance, first-year high school student Kazuhiko Nukumizu still ponders how he would respond if his life were transformed into a love story. Nevertheless, as a self-described "background character," Nukumizu is content to persist in his life as an introvert with a minimal social presence. However, he unexpectedly finds himself too near the spotlight when he observes his popular classmate Anna Yanami being rejected by her childhood friend in the middle of a family restaurant. While Nukumizu wishes he could simply forget what he witnessed and move on, Anna ends up forcefully confiding in him, lamenting her status as a childhood friend destined to have her beloved stolen. As he becomes drawn into Anna's predicament, Nukumizu soon gets entangled in the relationship drama of two additional girls: Lemon Yakishio, an outgoing member of the track and field club; and Chika Komari, a shy member of the literature club. Now forced out of his comfort zone, Nukumizu finds himself a major character in the lives of far too many losing heroines.