No one can resist desire… Located on the easternmost continent of the world. This land, known as "Fire's Origin," is under threat from the Oni led by one of the Demon Kings—King Famine. To satisfy their own "desires," Famine and the Oni attack humans. Women attacked and devoured by the Oni will "degenerate into beasts," craving violation until they become pregnant; Men attacked and devoured by Famine will "degenerate into Oni," becoming evil spirits driven by desire.

In this desperate situation, there exists an unknown group whose mission is to fight and eliminate the Oni. These are the female ninjas led by Aoba, the leader of the Aoi clan. These so-called "female ninjas" fight the Oni day after day. One day, Aoba orders the ninja Tsumi to capture Famine alive. Tsumi successfully captures Famine alive using the Aoi clan's secret techniques, however… "Aoba's hidden desires," "Famine's insatiable desires," "Tsumi's unearthed desires" These intertwined desires gradually consume all of Fire's Origin.