When a samurai is brutally murdered in a Kyoto tea house, ninja master Hiro Hattori has three days to find the killer. Otherwise, the revenge-driven son of the dead samurai will kill the beautiful geisha accused of murder and Mateo's father, the Jesuit priest whom Hiro has sworn to protect with his life. The investigation leads Hiro and Father Mateo into the dangerous waters of the floating world of Kyoto, where they quickly learn that everyone, from the owner of the tea house to the dishonored brother of the murdered man, has a reason why they want to keep everything a secret.