In the world of ninjas and the shogun, honor is everything. When the Samurai Lord Inaba is discovered murdered in his sleep while under the protection of the shogun, the ruler is honor-bound to find the killer. Desperate for justice, he turns to the famous Judge Ooka—the Sherlock Holmes of eighteenth-century Japan—and his fourteen-year-old apprentice, Seikei, to investigate. Their one clue? A bloodstained origami butterfly. Determined to unmask the killer, Seikei embarks on an adventure filled with mysterious and deadly shape-shifting ninjas, vengeful peasants, and a killer who will stop at nothing to keep his true identity hidden.