Rosalita encounters a green cloud in an abandoned silver mine and thinks that it is a ghost, while her hired hand believes it to be the Coyote spirit. However, after miners are found to be severely dehydrated, Burt, with Twitchell and Tyler investigate the mine to discover the gas themselves. Barely managing to escape from the cloud by using a bottle of water as a decoy, everyone regroups and Cletus, a scientist who previously worked in a laboratory near where the cloud is, deduces that it is a hydrophilic bacteria that was a project of the lab. However, after it was boarded up, it must have fell into a container of Mixmaster, a compound that blends non-human DNA originally used to created living weapons for the government. Knowing that it will be drawn to the town for moisture, they decide to trap it in a special container using a makeshift vacuum cleaner built by Tyler and Cletus. The National Guard is sent to evacuate them for a napalm bombing, but Jodi and Rosalita stall them by summoning El Blanco and using him to block the road. Thanks to a distraction by Nancy and Cletus, the men are able to finish the makeshift device and Tyler sucks the creature in. They then have Twitchell send it away for proper government storage. However, Cletus brings bad news as that the cloud spread Mixmaster throughout the area it traversed and soon the wildlife and plant life will merge into new creatures.