Haunted by his failures, Etsurou Kurosu contemplates suicide as a final escape. In a desperate moment, he stumbles upon his neighbor Rio Miyaichi's dark secret—a penchant for murder. Instead of silence, Rio offers him a chilling deal: embrace her true self. As their twisted relationship unfolds, Kurosu is thrust into a world of violence and intrigue, torn between survival and unraveling the enigma of his deadly companion.