The provided text focuses on the dramatic events surrounding the investigation of a long-ago murder during a time of intense political rivalry in feudal Japan. Sano, a high-ranking official, is ordered to find the killer of the shogun's cousin, Tadatoshi, whose skeleton was recently discovered. This investigation is complicated by the machinations of Lord Matsudaira, Sano's bitter rival, and the unexpected reappearance of Yanagisawa, an exiled foe, both of whom use the murder to frame Sano's mother, Etsuko. A key revelation shows that Etsuko, along with two men (Egen and Doi), murdered Tadatoshi decades earlier because the boy was a dangerous arsonist responsible for spreading the Great Fire. Sano must also contend with the immediate danger posed by Lord Matsudaira, who orders the assassination of Sano, his wife Reiko, and their children after Matsudaira is put under house arrest. Ultimately, Sano uses the staged execution of Yanagisawa's son, Yoritomo, to draw out Yanagisawa, exposing both him and the truth about Etsuko's past actions, though the political struggle with Yanagisawa is far from over.