In this world, people live alongside half-breeds and beasts. Kannaduki Eitarou is a handyman, single, and only has one family member: his little brother, Mikage. They are both half-breeds (human and wolf) but where he seems to have no unusual traits, Mikage is a different story. He has wolf ears and a tail, and if the moon is full, he falls unconscious and transforms fully into a giant wolf. He won't remember anything from that time though. It seems Eitarou's days are consistently riddled with problems!