Camp Green Lake was built near an abandoned town in an unmamed location in Texas. The town used to be near the largest lake in the state but became a dry, burning hot area after Sam The Onion Man was killed on the lake 110 years earlier by Trout Walker. The Camp is run by the Warden, and her assistant Mr. Sir, and Stanleys Group is mainly controlled by counselor Mr. Pedenski. Each day, the boys must dig a hole as wide and as deep as their shovel in the desert to make themselves better. However, after Stanley, carried Zero, a bloodline of Madame Zeroni's family up to the top of God's Thumb, he broke the curse that had been with Stanley's family for generations. When Stanley is found not guilty and is released from the camp, it rains again for the first time in 100 years and the Warden, Mr. Pendanski, and Mr. Sir are all arrested.  Camp Green Lake is shut down and turned into a Girl Scout Camp because of this. 

God's Thumb is a mountain on the other side of Camp Green Lake. When the lake had water, God's Thumb was on the other side of the town. At the top of God's Thumb is a natural water source and onion farm where the water flows uphill. Sam had his secret onion farm on top of God's thumb. After Stanley was left alone in the desert, he found his way to God's Thumb and all the water and onions he could ever want. When Stanley escaped Camp Green Lake to find Zero, they went to God's Thumb. Stanley and Zero had onions and drank the water from the spring that ran uphill.