Long ago, a Spider Yokai once killed a lot of people; but a brave monk challenged her.
In modern day; a young used bookseller, Suzuri, and his landlord's granddaughter, Mizuki, crack a sealed book that had an offspring of that spider. The spider takes the form of a young innocent child; and they agree to take care of her.
But what seems like a heartwarming tale turns into one of horror...
- Animals Hate Him: Dogs and cats aren't very fond of the spider girl.
- Cute Little Fangs: Which are still sharp enough to draw blood.
- Cute Monster Girl: Horribly subverted; the cute appearance is an act; and she ultimately sacrifices Mizuki to her mother and shapeshifts into her.
- Cuteness Proximity: Suzuri can't help but fawn over the little yokai.
- Downer Ending: Mizuki is eaten by the spider's mother, and the spider-child masquerades as Mizuki without anyone being the wiser.
- The Farmer and the Viper: Although their relationship is vitriolic at best, Mizuki allows the spider girl to stay in the shop and helps look after her. She gets killed for it.
- Giant Spider: The mother who attacked the village all those years ago.
- History Repeats: The same events happened to the monk. The current day cast even read about it.
- Hope Spot: Just as they're about to fall into the mother's clutches, Suzuri and Mizuki both land on top of a web overlooking the lake. The spider girl lands beside them and points to her mother below, showing how beautiful she really is... just before severing the web keeping Mizuki suspended.
- Lured into a Trap: Pay close attention to the old bookkeeper's wording. Furthermore he seems nonchalant about the existence of yokai... probably because he seems to have gone though something similar that Suzuri went through with a different kind of monstergirl.
- Nature vs. Nurture: Nature wins... Not that there was even a fight to begin with.
- Plot-Relevant Age-Up: The spider girl appears in an adolescent form when summoning her mother.
- She later stays in the form of a full adult after replacing Mizuki.
- Red Eyes, Take Warning: The spider girl's eyes are red, and it's usually pretty cute. Not so much when they start glowing.
- Yōkai: The titular character.