Kou Yamori appears as a typical middle schooler on the surface, excelling academically and getting along well with his peers. However, he grows tired of keeping up this facade and decides to leave school, which triggers insomnia due to the lack of daytime distractions. Taking nightly walks, he finds solace but knows his sleeplessness is a serious issue. During one of these walks, he encounters a peculiar girl named Nazuna Nanakusa, who identifies the root of his sleep problems: his reluctance to embrace true freedom despite making changes. She asserts that he must find contentment in his waking life to conquer his insomnia. After what seems like a resolution of his troubles, Nazuna invites him to her place and shares her futon with him. In a surprising turn of events, as she leans in close, she bites his neck, unaware that Kou is only pretending to be asleep.