Set in a world where humanity has been ruled by fungi and all freedoms have been taken away by the Amigasa government, Dante, a soldier, lives in Area D-18, which is controlled by the government. One day, Dante is assigned to a top-secret mission that forces him to travel outside of Area D-18. While on the mission, he meets a woman named Aoi. After talking with her, he begins to distrust the government and joins a rebel organization to stand up against it.