On the surface, Kou Yamori appears to be an ordinary middle school student. He works hard to maintain this image while being somewhat good at school and friendly with his classmates. However, one day he decides to stop pretending and quits school, getting sleeplessness as a result of having no outlet for his energy throughout the day. He feels marginally better when he walks alone at night, but he is aware that his inability to sleep is a severe issue. On one of these walks, Kou meets a strange girl named Nazuna Nanakusa, who diagnoses the source of his insomnia: despite making improvements in his life, he is still preventing himself from enjoying genuine freedom. He won't be able to sleep unless he does.