In a post-apocalyptic Japan, a wind reminiscent of a plague ravages its arid and sand-filled terrain. The wind's aftermath leaves rust as the only trace of life it spares. The culprit of this abject environment is attributed to mushroom spores. A notorious archer by the name of Bisco Akaboshi, who is branded as the "Man-Eating Mushroom," is hunted for his ability to grow mushrooms with ease. In reality, he's a "Mushroom Protector" who's determined to regenerate the land by distributing fungi that could revert it to its former state. Accompanied by the crab Akutagawa and young doctor Milo Nekoyanagi, Bisco sets out on a mission to locate the fabled "Sabikui" - a miraculous mushroom that devours all types of rust.
