Known only as "Ninja", these mysterious mercenaries have worked in the shadows of history from ages past.Dealing in espionage, secret plots and assassination, the ninja brought prosperity to Daimyo and Feudal lords from the shadows.
In the village of their ancestors, ninja continue to leave for training, as is tradition. However, due to lack of requests for work, the village has become nothing but a small gathering of houses in the mountains.
It is from this village that Sumire was commanded to leave, with orders to train in the city by her father, the village chief.
However, lacking food and money, she collapses on the side of the road.
Saved by the main character, she is determined to repay her debt to him and suddenly becomes an uninvited guest as his house...