A scream sounds... and the villagers wake up. Too late: the victim lies, the throat shredded, while a female silhouette flees into the night. It is the sixth victim in a month. Dosan-san, the right arm of the shogun is sent to investigate this case. But, the more he advances, the more he understands that he is on the trail of creatures far more dangerous than anything he has ever faced.Furiko, the most dangerous of the Sisters of the Shadow is not far away.