Mariko Oshiro is not your average Tokyo cop. As the only female detective in the city’s most elite police unit, she has to fight for every ounce of respect, especially from her new boss. While she wants to track down a rumored cocaine shipment, he gives her the least promising case possible. But the case - the attempted theft of an old samurai sword - proves more dangerous than anyone on the force could have imagined.

Detective Sergeant Mariko Oshiro has been promoted to Japan's elite Narcotics unit - and with this promotion comes a new partner, a new case, and new danger. The underboss of a powerful yakuza crime syndicate has put a price on her head, and he'll lift the bounty only if she retrieves an ancient iron demon mask that was stolen from him in a daring raid. However, Mariko has no idea of the tumultuous past carried within the mask - or of its deadly link with the famed Inazuma blade she wields.

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.

The Tiger on the Mountain is a legendary blade, crafted by the master swordsmith Inazuma, and reputed to possess magical powers. In 1442 Japan, the sword dwells inside the impregnable fortress of Hirata Nobushige, the enemy of the Iga clan. Venerable shinobi Jujiro has recruited the brave young ninja Tada to steal the sword and restore power to the Iga clan. If Tada is successful, he’ll go from being the clan’s orphaned ward to a legend for the ages - and he’ll be able to ask for Old Jujiro’s granddaughter’s hand in marriage.