A high school girl named Ayame has the outward appearance of being listless due to severe fatigue caused by a mysterious case of insomnia. Because of this, she exhibits traits of a Himono Onna by going home after school and immediately collapsing in her bed. As the line between dreams and reality begins to erode, tormented by sleeplessness day and night, Ayame soon has a waking dream predicting her younger sister Hiiragi dies. Ayame then fights against her dream alone.