A quiet middle school girl named Nadeko Sengoku has always hidden behind long bangs and a hat, speaking in a hesitant third-person voice with her go-to phrase being a soft I’m sorry. Years earlier, a jealous classmate attempted to curse her with a charm, but through a mistaken ritual at a forgotten shrine, Nadeko ended up genuinely cursed by snakes on her own. She was rescued by Koyomi Araragi, the big brother figure she secretly loves, who chopped the serpent apparition to pieces. However, desecrating a shrine dedicated to a snake god has consequences that are about to resurface.

Now Nadeko finds herself haunted once again, this time by a giant snake who calls himself Kuchinawa, a deity demanding her help in locating his missing object of worship. The mysterious Oshino Ougi approaches Nadeko with unsettling advice, telling her that no one can remain a victim forever. Nadeko, who has long internalized the role of the helpless, cute girl who needs saving, begins to follow the snake god’s demands. As she searches for the object of worship, the pressure of her unrequited love for Araragi, the judgmental eyes of her classmates represented as faceless outlines, and her growing resentment at being cast as a perpetual victim all converge.

The narrative, told entirely from Nadeko’s deeply unreliable perspective, reveals that she is far from the innocent she pretends to be. After obtaining the object of worship, she makes a devastating choice. Rather than surrendering it, she swallows the object and transforms into a snake apparition herself, gaining immense power. Now a god, Nadeko’s true feelings surface no longer the shy girl asking for help, she becomes a cruel and selfish force determined to kill Koyomi Araragi and his companion Shinobu Oshino. The story culminates in a surreal confrontation where Hitagi Senjougahara, Araragi’s girlfriend, forces Nadeko to confront her own lies and self-deception, pushing the arc toward a tense and psychological breaking point. The setting shifts between Nadeko’s middle school, the forgotten shrine, and the town, with the visual and narrative framing emphasizing her sense of entrapment behind bars, railings, and her own constructed persona.