Japan, 1703. On a snowy night, forty-seven warriors murder a man who stood at the center of the scandal that turned them from samurai into masterless ronin two years before. Clearly this was an act of revenge—but why did they wait so long? And is there any reason they should not immediately be ordered to commit ritual suicide? Sano Ichiro, demoted from Chamberlain to his old post as Most Honorable Investigator of Events, Situations, and People, has mere days to solve the greatest mystery of samurai legend—while his own fortunes hang in the balance.