A failed assassination attempt brings into Freeman's possession Muramasa, the Devil's Sword, an ancient blade that brings misfortune and death to any who possess it. To tame the sword's malevolent spirit, Tiger Orchid, Freeman's wife, takes the blade to train with a legendary swordmaster, but she'll need to find him in the Kowloon Walled City, a slum so virulent that it does not officially exist. But its dangers are all too real, including a criminal army bent on selling Tiger Orchid into slavery.