Mr. and Mrs. H. Chatterton Chimpanzee are leading citizens in the aristocratic suburb of Cocoanut Grove. They have only one grief in life: the stupidity of their son Chip-Cheloogoo Chimpanzee. Though they named him after a leading chimp philosopher, Chip-Cheloogoo consistently disappoints his parents. They interpret his regular habit of playing practical jokes on them as a sure sign of deficient intellect. Their son, on the other hand, thinks it is their conventional life that is intolerably stupid; one day he decides to run away from it.
He ends up in a distant part o the jungle, where he finds an iron cylinder in a clearing. The object is in fact a big old camp stove left behind by some forgotten troop of human hunters; but Chip knows his forest lore, and recognizes it as the famed Great Oracle. As he watches from hiding, jungle animals come one by one to offer tasty treats to the Terrible Unknown: they toss fruits and nuts into the door of the stove, and ask a question. They receive their answers from a deep echoing voice within.
After a day of watching, Chip has noted that the answers given by the Oracle tend toward the double-talk typical of phony prophets and fortune-tellers. He also explores the area, and finds the opening of a tunnel concealed by brush in a nearby ravine. He follows the tunnel to a large artifical room underground, chock-full of good things to eat, plus coins and gemstones, knives and hatchets, and a range of other objects that have served as gifts to the Oracle. He sees that the room connects with the bottomless stove in the clearing above. And Chip also finds the Oracle himself — none other than the philosopher after whom young Chip was named.
The older chimp is not happy to be discovered; he talks glibly, but lunges at young Chip with a knife. The young animal grabs a nearby hatchet for self-defense. After a tense standoff, young Chip convinces his older counterpart that the other animals have also figured out the imposture, and will come to hunt and kill the false Oracle. Terrified, the old chimp flees for parts unknown; and young Chip inherits a very comfortable livelihood — not bad for a "stupid" chimpanzee.
The theme of stupidity versus intelligence dominates the tale. The superficial assertion that Chip is deficient is negated by his actual cleverness in the story's action.
Baum gives a similar comic picture of chimpanzees in The Woggle-Bug Book. Here in the story though, he makes the mistake of giving chimpanzees tails.