A young man named Amenashi is haunted by the death of his younger sister Anna, who took her own life after witnessing a classmate’s suicide in high school. Burdened by guilt, he continues to chase her memory. One night, he learns of a secret mass suicide event held in a Tokyo nightclub and is drawn to it. His close friends, Nozu and Hattori, grow suspicious and follow him inside. In a closed-off space filled with despairing youths, the three attempt to escape, but are ultimately forced to confront the emotions they have each been carrying deep within.