In a Japan turned to desert by the rust-spreading "Rusty Wind," archer Bisco Akaboshi is hunted as the "Mushroom Criminal" for spreading the fungi blamed for the blight. With the young doctor Milo Nekoyanagi, Bisco sets out to find the Sabikui, a legendary mushroom said to devour rust itself and cure his dying mentor Jabi. This manga adapts the first light novel volume.