Everything started from an old book telling the story of an expert yin-yang master who defeated a giant spider in ancient times. Antique book dealer Amane Suzuri, who is trying to sell the book in order to pay the rent, would have never imagined that after reading this story to Mizuki, the building owner's young granddaughter, he could find himself face-to-face with a scared, twenty-centimeter-tall, eight-legged baby arachnid girl. And she's the sweetest thing in the world... or not?