On a desert planet settled by people from Earth, the red-coated gunman Vash the Stampede carries an enormous bounty and a reputation for catastrophe. Outlaws and bounty hunters roam settlements dependent on artificial life forms called Plants for their energy.
The frontier landscape has a technological dependency beneath it: towns survive through the resources supplied by Plants. Vash's official designation as a human disaster makes reputation part of the danger around him. This is the 1998 anime, separate from the later Stampede adaptation and its continuation.
An early dispute centres on a town's water supply. Meryl and Milly find the man they have encountered working as a bodyguard under Vash's notorious name, bringing reputation into a very local struggle over a resource. The desert matters as an inhabited place whose residents need something more reliable than a gunman's legend.