When Tokyo falls victim to a deadly terrorist attack, Detective Sergeant Mariko Oshiro knows who is responsible, even if she doesn't have proof. She urges her commanding officers to arrest the perpetrator—an insane zealot who was just released from police custody. When her pleas fall on deaf ears, she loses her temper and then her badge as well as her best chance of fighting back.
Left on her own, and armed with only her cunning and her famed Inazuma blade, Mariko must work outside the system to stop a terrorist mastermind. But going rogue draws the attention of an underground syndicate known as the Wind. For centuries they have controlled Japanese politics from the shadows, using mystical relics to achieve their nefarious ends—relics like Mariko's own sword and the iron demon mask whose evil curse is bound to the blade. Now the Wind is set on acquiring Mariko.
Mariko is left with a perilous choice: Join an illicit insurgency to thwart a deadly villain or remain true to the law. Either way she cannot escape her sword's curse. As sure as the blade will bring her to victory, it also promises to destroy her.