​In the days that followed the end of the world, few could have predicted the Rust Wind, a phenomenon that swept across Japan like a plague, choking the life from the land and its people and corroding flesh into brittle, iron sand. No one knows how the Rust began, but one mushroom-wielding renegade known as Bisco Akaboshi, the Man-Eating Redcap, is determined to bring about its end. He's the latest in a long line of Mushroom Keepers, and together with the dashing young doctor Milo Nekoyanagi, the two will brave the horrors and wonders of the Iron Desert in search of the Rust-Eater: a mythical mushroom rumored to have the ability to cure the ailment once and for all.