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.

The owner of the sword, Professor Yasuo Yamada, says it was crafted by the legendary Master Inazuma, a sword smith whose blades are rumored to have magical qualities. The man trying to steal it already owns another Inazuma—one whose deadly power eventually comes to control all who wield it. Or so says Yamada, and though he has studied swords and swordsmanship all his life, Mariko isn’t convinced.

But Mariko’s skepticism hardly matters. Her investigation has put her on a collision course with a curse centuries old and as bloodthirsty as ever. She is only the latest in a long line of warriors and soldiers to confront this power, and even the sword she learns to wield could turn against her.