While guarding the hideout in Otaru, Natsutarou obtains information about a tattooed human skin brought to an oil merchant running a gambling den. Hoping to achieve a feat and earn Hijikata's recognition, he plots to steal it. In the midst of this, he encounters the escaped convict "Lightning Bandit," Keiichirou Sakamoto, and the vicious female thief "Viper Ogin" in front of the shop, and ends up assisting them in raiding the gambling den. Natsutarou is eager to obtain not only the tattooed skin but also Sakamoto's tattoo. However, it is revealed that the tattooed skin at the oil merchant's is a trap set by Lieutenant Tsurumi...