In order to restore control on the finances of the shogunate, Arai Shiraishi, a close associate of the sixth shogun, Tokugawa Ienobu, selects Mizushiro Soshiro as the Shogun's account auditor. The samurai is initially bewildered by his new, unfamiliar role, but he comes to understand, when he is attacked by one assassin after another, as he tries to uncover corrupt officials who are lining their own pockets with the shogun's money.