During a horse race at Edo Castle, the shogun's intelligence chief, Ejima Senzaemon, falls dead. The death of a high-ranking official is ordered to be investigated by Sano Ishiro. At the same time, Sano's wife, Reiko, is present at a trial where a beautiful young woman is accused of the deaths of her parents and sister. The woman confesses, but the judge delays his verdict and asks Reiko to prove guilt or innocence. defendant. As they investigate further, Sano and Reiko come to the conclusion that these crimes are somehow related.