In ancient times, Tokyo faced a monstrous spider's wrath, until a fabled exorcist intervened, sealing the creature with divine might. Centuries later, Mizuki Henmi, a young girl, stumbles upon a valuable book in Shu Suzuri's ancient bookstore. Accidentally breaking its seal, she releases a charming spider-like entity. As the trio's bond forms, peculiar winds stir unease. While Shu befriends the spider, Mizuki senses a darker presence looming, sparking tension and mystery in their lives.