Mother's Chaos is adapted from the adult game by Alice Soft. In a secluded village deep in the mountains, there is a house with a young man named Kojiro living in it. The secret of this house has been hidden on the surface. The village has long been troubled by a low birth rate, and to address this issue, the village chief relies on women from the Kamishiro family. This is referred to as the 'Feast'. The protagonist Mamoru and his 'onee-chan' Kotone are the only survivors of a fire that happened ten years ago. The homeless were taken in by the Kamishiro family. However, Kotone was taken to the eldest daughter, and Mamoru became a servant. They soon thought of the 'Feast,' leading them to decide to use Kotone. Due to her responsibilities to her family and Mamoru, Kotone accepted this situation. Knowing the truth about the feast, Mamoru cooperated with her out of necessity...