Leading an unremarkable high school life, "You" finally resolved to make a change. You enrolled in a university far from your hometown, successfully making your so-called "college debut."
There, a younger student named "Kou" appeared, and you soon grew close to him. The two of you enjoyed your days together until one day, the conversation turned to a person named "Yagi-kun."
From that moment on, Kou began to exhibit increasingly suspicious words and behavior...