Japan, 1704. Tsuruhime, the shogun’s daughter, dies of smallpox after the earthquake that has already weakened Edo. With no grandchild to inherit, the ageing shogun recognises Yoshisato, a young man raised as Yanagisawa’s son, as his own heir. Sano suspects that the claim is a political construction.
Evidence that Tsuruhime may have been murdered turns the succession dispute into a criminal investigation. Sano and Reiko are accused as rival factions move to eliminate them, and the safety of their children becomes inseparable from the future of the regime. Establishing the cause of one woman’s death may determine who rules Japan.