Officer Mondo Nakamura has a mundane career as a policeman, spending his days patrolling the streets of Edo, and his nights being bullied by his wife and mother-in-law. He is also the leader of an elite cadre of assassins. There is the roofer who uses sharpened roof tiles. There is the samisen maker who kills with his instrument's strings. And then there are others. Each killer has a style based on his daytime profession; together, they serve those who seek justice and revenge. But they are not the only avengers. When hit men across the city are slaughtered, each is left with a copper coin in his mouth to pay the ferryman to hell. It becomes apparent that someone is looking to become Edo's only assassin! Mondo and his team must act quickly and find the "Copper Coin Killer" before he finds them!