The beautiful young Kagero with the body of poison joins her Koga Ninja friends in their investigation of a plague that was causing numerous deaths throughout villages. However, her team members were annihilated by Tesai, one of the 7 Demons of Kimon, and she was taken as a sex captive. She was rescued by the wandering swordsman Jubei and was able to report to her apathetic lord the deaths of her people.

Meanwhile, Jubei's expertise in combat and the death of the first Kimon Demon by his hand reaches the rest of the other Demons. They try to outdo each other in their plans to defeat the elusive samurai.

Later, Jubei was hired by the mischievous Dakuwan, by way of blackmailing, and they combined forces with Kagero in search for the root of all the destruction surrounding them. They met the 6 other Demons of Kimon along the way, and the battles led them closer to the lurking evil that bound them together and to the tragic past that had began to haunt Jubei once more.