While Stanley spends another day digging holes, he thinks about God's thumb and wonders if Kate Barlow lived in this area and if it was actually her gold lipstick tube that he found. When Mr. Pendanski delivers their bag lunches the other boys taunt Stanley about having Zero dig Stanley's hole for him. Zigzag pushes Stanley, who doesn't want to fight. Mr. Pendanski comes over and tells Stanley to fight back. Stanley softly hits Zigzag who in return pummels Stanley and jumps on top of him. Zero attacks Zigzag and almost kills him until Armpit breaks them up. Mr. Pendanski fires his pistol into the air and the Warden arrives. The boys tell the Warden that Zero has been digging some of Stanley's hole. Stanley explains that he's teaching Zero to read and Mr. Pendanski says, " You might as well try to teach this shovel to read! It's got more brains than Zero." The Warden spells some words for Zero and when he pronounces h-a-t as chat everyone laughs at him. The Warden forbids Stanley to teach Zero to read and Mr. Pendanski taunts Zero about how stupid he is. Zero says that he will not dig any more holes and when Mr. Pendanski tells him that digging holes is all he'll ever be good for, Zero smashes his shovel across Mr. Pendanski's face and runs away. The Warden tells the other counselors not to bother about Zero because he'll have to return for water. Then she says that the remaining six boys must still dig seven holes.
Stanley is angry with everyone, including himself. He regrets having Zero dig his hole for him. He considers ways to help Zero but can not think of any that do not involve retribution from the Warden. He hopes that Zero will travel to the mountain that looks like a thumb. Mr. Pendanski and the Warden ask Stanley if he knows where Zero is and then they discuss how they will change Zero's records so that no one will ever find him. Mr. Peandanski and the Warden say that they do not want anyone in the A.G.'s office to know about Zero. In the end they decide that no one will care about Zero.
A new boy, who was arrested for stealing cars, is assigned to Zero's cot. His name is Brian but X-Ray names him Twitch because he fidgets. Stanley continues to worry about Zero and when Mr. Sir drives in the truck to give them water, Stanley impulsively decides to steal it. He doesn't know how to drive but Twitch yells a few directions at him and Stanley races away. Soon Stanley drives the truck into a hole. He gets out and runs away.
No one follows Stanley as he runs away from the truck. He encounters many holes as he walks, and a family of yellow-spotted lizards in one of them. He runs away from the lizards and later finds one sunflower seed in a burlap bag.
Stanley walks towards the thumb mountain but is exhausted. He sees something in the dirt and finds that it is part of a boat named Mary Lou. There is a hole under the boat and Zero is in it.
Zero looks sick but refuses to go back to camp. Stanley and Zero go under the boat where it is cooler. Zero still has his shovel that he used to hit Mr. Pendanski. Zero has found many jars of a muddy looking liquid that he calls sploosh. Stanley doesn't want to drink it because he realizes that it is probably at least 100 years old, but he is so thirsty that he does. It tastes like peaches. Zero and Stanley have to break the top off the last bottle of sploosh because it is sealed very tightly. Zero has a bad stomachache and Stanley thinks it might be from the sploosh.
The novel establishes links between the past and the present. Just as the town of Green Lake's violence towards Katherine Barlow and Sam forced Kate to turn to violence and crime one hundred and ten years ago, so Mr. Pendanski's repeated taunting eventually drives Zero towards violence. Mr. Pendanski, who has always shown signs of being cruel underneath his kind façade, begins to show his true colors as he taunts Zero. Far from wanting every boy to turn his life around, Mr. Pendanski seems to want to keep Zero in his dead-end situation at Camp Green Lake. Stanley realizes that people should be proud of Zero for not only learning how to read, but for wanting to read. The Warden and Mr. Pendanski, on the other hand, seem determined to keep Zero from learning anything. Kate's story becomes directly intertwined with Zero and Stanley's story when Zero finds shelter in Sam's old boat, MaryLou.
The "sploosh" that Zero survives on is undoubtedly the celebrated spiced peaches that Katherine made during her days as a school teacher. The objects that remain from Sam and Kate Barlow, like the spiced peaches and the broken boat, aid Zero and Stanley in their struggle to escape the persecution and cruelty of Camp Green Lake, which is similar to the persecution and cruelty that Kate and Sam faced one hundred and ten years ago from the citizens of Green Lake. Stanley demonstrates his changed character when he steals Mr. Sir's truck. Although he knows that the Warden will surely punish him if and when she finds him, Stanley is brave enough to leave camp in order to try and help his friend. This willingness to suffer in order to help Zero shows that Stanley is not only brave, but also a good friend. He and Zero have successfully broken the Warden's system of authority and they are willing to help each other. Although the Warden and Mr. Pendanski decide that no one will care about Zero, Stanley proves them wrong by trying to help Zero on his own. The pieces of the mystery are almost all in place at this time. Katherine Barlow and her connection to Stanley's life and history is clear, the Warden's desire to have the boys dig for Kate's treasure has been revealed, and Zero and Stanley's family ties have also been discovered by the reader. What is left now is to discover how Zero and Stanley will survive in the unfriendly desert with dangerous lizards and the constant threat of dehydration. Obviously, God's thumb will be their source of refuge but what they find there is still unknown. In addition, the Warden mentions the A.G., a new and mysterious character.