The main character of Grauen no Torikago is a 16-year-old schoolgirl named Nao Tsunoda. Recently, she decided to start living separately from her parents - and moved to Tokyo’s Grauenheim apartment complex. But one day, Nao’s life turns into a nightmare when she suddenly discovers the headless corpse of her neighbor (Erica Shimizu) on the roof of the house.

And having entered a neighbor's apartment, Nao sees an even more eerie scene: music from the opera Faust plays in the room, and Erica’s severed head hangs from the ceiling and makes strange howling sounds! The killer snapped the girl's head and connected it through a hose to the gas pipe so that the head “sang” to the music from the CD player ... But why did the killer do it? Just out of a desire to mock the corpse, or is there a secret meaning in its actions?

Soon the chain of brutal murder continues - and it becomes clear that a psychopath is hunting the inhabitants of Grauenheim. Moreover, it not only kills people, but also disfigures their corpses so that they carry a certain symbolism in themselves. Will our heroine be able to unravel this symbolism and reveal the identity of the killer, or is she destined to become another victim of a maniac?