Japan, 1709. Sano has been reduced to patrol duty, his marriage to Reiko is damaged and his enemies Yanagisawa and Lord Ienobu have formed an unexpected alliance. When the ageing shogun is stabbed inside his palace with an iron-ribbed iris fan, Sano is restored as chief investigator.
The attack places every succession faction under suspicion, including Sano’s former ally Hirata. An incorrect accusation will allow the future ruler to destroy Sano’s family without restraint. The final investigation forces Sano and Reiko to decide which loyalties can survive the end of Tsunayoshi’s reign and whether justice is possible within a collapsing court.