Studio Izumo concept work

In this concept there is a small description:
The story of one of the girls of the warriors, who goes in search of the missing twenty years ago the hero. There are a few clues that it should - he disappeared immediately after defeating the demon king in the forest of magical power. Upon arrival in the woods the girl is poisoned by an unknown substance. Fortunately she is saved by the woodsman who lives in the forest of magical power. However, to completely withdraw the poison from her system she would have to have sex with the gamekeeper.