A theatrically-inclined pet chameleon becomes stranded in the Mojave Desert when his terrarium falls out of his owners’ car. Seeking refuge, he encounters a nine-banded armadillo named Roadkill, who tells him about a town called Dirt and the mystical “Spirit of the West.” Determined to find help, the chameleon ventures into the desert, where he narrowly escapes a dangerous red-tailed hawk. He eventually meets a desert iguana rancher named Beans, who takes him to the town of Dirt.

In Dirt, the chameleon adopts the persona of “Rango” and quickly finds himself in trouble with the local outlaw, Bad Bill. Rango’s accidental defeat of the hawk leads the townsfolk to mistakenly believe he is a hero. They appoint him as their new sheriff, much to the dismay of the town’s elderly mayor and the worried townsfolk who fear the return of the infamous gunslinger Rattlesnake Jake.

Faced with a severe water shortage due to a drought, Rango is tasked with investigating the missing water. However, he inadvertently helps a gang led by Balthazar steal the water supply, mistaking them for legitimate prospectors. Rango’s posse later discovers the banker Johannes Merrimack III dead, apparently drowned despite being in the desert. The stolen water is found to be empty, and Balthazar and his gang are detained, but the mystery remains unsolved.

The mayor is eventually revealed to be behind the water shortage, having manipulated a pipeline to Las Vegas to buy up the town’s land for himself. After Rango meets the Spirit of the West, he returns to Dirt determined to set things right. He uncovers the shut-off valve in the pipeline and returns to confront the mayor. Despite being forced to surrender to save Beans’ life, Rango outsmarts the mayor by taking the bullet from his own gun, which allows him to free himself and Beans.

In the end, Rango earns the respect of the townsfolk and Rattlesnake Jake, who kills the corrupt mayor in revenge. With the water supply restored, Dirt celebrates Rango as a true hero, solidifying his place in the town’s history.