Painted Valley was home to a community of chimpanzees some distance from Ape City, cut off from the outside world by a high mountain pass which ran by Mount Lam. In the distant past the chimps of Painted Valley had overthrown their orangutan and gorilla overlords and thrown them into a pit inside a cave. Forty years before Taylor came to earth, an earthquake caused the river that flowed through Painted Valley to become contaminated by the Forbidden Zone, and in subsequent years a number of chimps had become mutated as a result. These mutants were banished to the caves, where they were fed by the community and projected mental images of monstrous creatures to scare away unwanted visitors. When Vitus, Milo and Cornelius visited Painted Valley in search of supplies they were initially welcomed by the leader, Amicus. But after they began to investigate the history of the area Amicus threatened to kill them because their knowledge would bring an end to their peace. Amicus' daughter, Chinda, was among the mutant chimps, and she left the caves to save the lives of the strangers. The mutants revealed they could disguise their features through their mental powers and were welcomed back. In return, the visitors agreed to spread the word that Painted Valley had been destroyed in the catastrophe of the Moon's destruction, and the mutants projected an image of a desolate valley for any future visitors.