When a samurai is brutally murdered in a Kyoto teahouse, master ninja Hiro has no desire to get involved. But the beautiful entertainer accused of the crime enlists the help of Father Mateo, the Portuguese Jesuit priest who Hiro is sworn to protect, leaving the master shinobi with just three days to find the killer and save the girl and the priest from the dead man's vengeful son. The investigation plunges Hiro and Father Mateo into the dangerous waters of Kyoto's floating world, where they quickly learn that everyone from the elusive teahouse owner to the dead man's dishonored brother has a motive to keep the samurai's death a mystery. A rare murder weapon favored by ninja assassins, a female samurai warrior, and a hidden affair leave Hiro with too many suspects and far too little time. Hiro must use his ninja skills in a secret mission designed to reveal the assassin's identity and save the Jesuit from execution. But the mission uncovers a host of secrets that threaten not only Father Mateo and the teahouse, but the very future of Japan.