The Ninja's Daughter

Autumn, 1565: When an actor's daughter is murdered on the banks of Kyoto's Kamo River, master ninja Hiro Hattori and Portuguese Jesuit Father Mateo are the victim's only hope for justice.
As political tensions rise in the wake of the shogun's recent death, and rival warlords threaten war, the Kyoto police forbid an investigation of the killing, to keep the peace—but Hiro has a personal connection to the girl, and must avenge her. The secret investigation leads Hiro and Father Mateo deep into the exclusive world of Kyoto's theater guilds, where they quickly learn that nothing, and no one, is as it seems. With only a mysterious golden coin to guide them, the investigators uncover a forbidden love affair, a missing mask, and a dangerous link to corruption within the Kyoto police department that leaves Hiro and Father Mateo running for their lives.
From the Trade Paperback edition.