Shuichi Saihara is an unremarkable high school student. One boring day follows another in an endless cycle. His life is filled with nothing but pure routine that has long been suffocating him.

The start of his final school year did nothing to change the situation. That is, until Shuichi came face-to-face with someone who had an infuriating smile and annoying behavior.

Unexpectedly, something in his life suddenly shifted with the arrival of this quirky new friend.