Mutilated snakes and a tree riddled with vile insults. This is the gruesome scene that Koyomi Araragi and Suruga Kanbaru witnessed while visiting a shrine deep in the mountains. Behind this horror is Nadeko Sengoku, a girl who has found herself in a twisted situation with a snake god. Koyomi feels that he must save her, but can he act fast enough to free Nadeko from the deadly grip of this newest aberration?