To win the heart of his pretty neighbor Audrey, Ted escapes from Thneedville, a totally artificial world where all vegetation has definitively disappeared, to go in search of a living tree.

Ted meets an embittered old hermit recluse in his cabin in the middle of nowhere, and discovers the legend of the Lorax, this creature as sullen as cute who lives in the beautiful valley of Truffula, who speaks in the name of the trees and who fights for the protection of nature.