"Which will come first: my resignation as a teacher or burning out past my limit?" Through the day-in and day-out responsibilities of his work, Nishiya is a teacher trying his best to be kind and caring to his students. However, as the days of long, grueling work hours, complaints from parents and guardians, and attempts to guide students falls on deaf ears pass, he finds himself gradually succumbing to fatigue no matter how much he reminds himself that this is the path that he chose. Sometimes...he even loses sight of who's sake he's living for. It is on one of those days, when the school district is rocked by a string of incidents, in which stray cats are slaughtered by human hands. And among the parents and guardians, a rumor is spreading that the culprit is a student who only attends school during exam week, a student named Hayasaka--.