The people have demanded change, Criterion boxes were created for the purpose of the people to leave their complaints in it. The result of this were two changes: the first being the creation of of 'Koishigawa Youjoujo' for the people, the second being an inner-city magistrate office, known as the Mushibugyo.

Tsukishima Jinbee is a warrior who aims to be best, under the belief that a weak warrior isn't a warrior at all. He was scouted out by a representative to join the Mushibugyo and told to go to Edo with the instructions that he'd knew what to do once he got there. Shortly after arriving at Edo, he hears a scream and goes to check it out... To find a giant spider-like creature devouring some citizens of Edo. Being a warrior, there's no way he could stand this...