Following the death of her grandfather, Hamaji Ooyama lives alone on a remote mountain, surviving by hunting. When her brother, a samurai in training in Edo, writes to her, he invites her to join him in the city. Upon arriving, she sees six dog heads displayed publicly—these belong to the Fuse, a group of eight part-human, part-dog beings causing trouble in Edo. After helping a strange man flee from pursuers, Hamaji reaches her brother's home. He asks for her assistance in capturing the last two Fuse members to collect a bounty offered by the Shogunate. However, the task is complicated because the Fuse can blend perfectly into human society, and the man she aided earlier shows traits typical of the Fuse.