One rainy day while Motoi and his friend, Reiichi were on their way home, they encountered a young girl who looked like a foreigner who then led them to a shop by a hill slope. There, they meet the shop owner, an old man named Shouten, who deals with exotic wildlife - both ordinary and unordinary: demon beasts.

Fascinated by the mysterious beasts the shop holds, Motoi agrees to work and raise a demon. Motoi's journey of encountering different demon beasts begins.