A wanted man and a pacifist doctor chase an impossible cure across a rust-eaten world, and the show treats their partnership like it matters more than saving the country. The action flies with genuine invention, arrows that bloom into obstacles, a giant crab that isn't comic relief, landscapes that feel actively hostile. This is adventure that knows rust consumes everything, including hope, and builds something alive anyway.
A centuries-old rust plague blankets Japan, consuming everything in its path and leaving the land a toxic wasteland. The only hope lies in a myth: a fungus powerful enough to devour the corrosion itself. Bisco Akaboshi is a wanted outlaw with a bow and a reputation, hunted for crimes he may not have committed. When he crosses paths with Milo, an idealistic young doctor searching for the legendary Sabikui mushroom, their goals align. Together with an oversized talking crab, this mismatched trio ventures into hazardous territories where rust storms rage and forgotten civilizations crumble. What begins as a simple treasure hunt becomes a race against time. Bisco fights not just enemies, but his own past and the weight of expectations placed on him. The journey tests whether an outlaw, a doctor, and a crab can actually save a dying world, or if some corruption runs too deep to cure. Part action-adventure, part buddy story, this anime balances earnest world-saving stakes with genuine humor and unexpected heart. The chemistry between its heroes carries you through landscapes both beautiful and broken.