Mr. Haddy takes Allie and his family upriver to Jeronimo. Allie meets the inhabitants and proceeds to start building a new, "advanced" civilization, inventing many new things in the process. The locals take kindly to Allie and his family, but Allie's will to build a utopian civilization keeps them working to their limits. Reverend Spellgood arrives to convert Jeronimo's citizens. In the process, Allie and Spellgood angrily denounce each other, leading to a permanent schism: Allie believes Spellgood to be a religious zealot; Spellgood believes Allie to be a communist. Allie sets to constructing a huge version of "Fat Boy" that can supply the town with ice. Upon completing the machine, Allie hears rumors of a native tribe in the mountains that has never seen ice. Allie recruits his two sons to carry a load of ice into the jungle to supply the tribe. Upon arriving, Allie finds that the load has melted, and that the tribe has already been visited by missionaries.