This book is a collection of twelve loosely connected short stories written by Edgar Rice Burroughs, comprising the sixth book in order of publication in his series about the title character Tarzan. Chronologically it is a midquel to the first Tarzan novel, Tarzan of the Apes, as the events recounted in it actually occur within Chapter 11 of that novel, between Tarzan's avenging of his ape foster mother's death and his becoming leader of his ape tribe.

Tarzan's First Love

Tarzan's courtship of the female ape Teeka ends in failure when her preference turns to their mutual friend, the male ape Taug. Tarzan wrestles with his humanness versus his ape-ness.

The Capture of Tarzan

Tarzan is taken captive by the warriors of a village of cannibals which has established a village near the territory of the ape tribe. He is saved from them by Tantor, the elephant.

The Fight for the Balu

Teeka and Taug have a baby (balu, in the ape language), which Teeka names Gazan and will not allow Tarzan near. She changes her mind after Tarzan saves the baby from a leopard.

The God of Tarzan

Tarzan discovers the concept of "God" in the books preserved in the cabin of his dead parents, to which he pays regular visits. He inquires among members of his ape tribe for further elucidation without success, and continues his investigation among the cannibals of the nearby village and the natural phenomena of his world, such as the sun and moon. Eventually he concludes that God is none of these, but the creative force permeating everything. Somehow, though, the dreaded snake Histah falls outside this.

Tarzan and the Black Boy

Jealous of Taug and Teeka's relationship with their baby, Tarzan kidnaps Tibo, a little boy from the neighboring village to be his own "balu." He tries with indifferent success to teach the terrified and homesick child ape ways. Meanwhile, Momaya, Tibo's mother does everything she can think of to find and recover her son, even visiting the hermit witch-doctor Bukawai, a terrible, diseased exile who keeps two fearsome hyenas as pets. He names a price for recovering Tibo she cannot afford, and she leaves disappointed. Afterwards, however, Tarzan, who is moved by Tibo's distress and his mother's love, returns the boy to her.

The Witch-Doctor Seeks Vengeance

Bukawai attempts to claim credit for Tibo's return and extort payment from the boy's mother, but is rebuffed. He plots vengeance against the native family and Tarzan, but is thwarted by the ape man.

The End of Bukawai

Bukawai, finding Tarzan unconscious after a storm, takes the ape man captive and stakes him out for his hyenas to devour. Escaping, Tarzan leaves the witch doctor in the same trap, in which Bukawai suffers the very fate he had intended for his enemy.

The Lion

Tarzan vainly attempts to impress on his ape tribe the necessity of maintaining a strict watch against the hazards and perils surrounding them. To drive home the lesson, he dons a lionskin he has taken from Mbonga's village and suddenly appears among them, only to find them more vigilant than he had thought, as they mob him and nearly beat him to death. He is saved only by the courage of his monkey friend Manu, which he had also previously under-rated, who risks all to reveal to Teeka and Taug that the "lion" is actually Tarzan.

The Nightmare

Having been unsuccessful hunting, Tarzan robs the native village of some rotten elephant meat, which he eats. Becoming ill from the tainted meal, he has a horrible nightmare, in which he dreams himself menaced by a lion, an eagle, and huge snake with the head of a village native. He is carried off by a giant bird but wakes in the fall from its graps, finding himself back in the tree where he'd gone to sleep. He realizes the incidents were not real. Subsequently attacked by a gorilla, he assumes that this too is a product of his fevered imagination, until actually wounded and hurt. He kills the beast, but is left to wonder what is real and what is fantasy. The only thing he is certain of is that he will never again eat the meat of an elephant.

The Battle for Teeka

Discovering bullet cartridges in his deceased father's cabin, Tarzan takes them with him as curios. Subsequently, Teeka is taken by an ape from another tribe, and Tarzan and Taug join forces to trail the kidnapper and rescue her. When they catch up, they are surrounded by the enemy tribe and nearly overwhelmed, until Teeka throws the cartridges at their foes in an apparently futile effort to help. When some of them hit a rock, they explode, frightening the hostile apes and saving her "rescuers."

A Jungle Joke

As part of his campaign of torment and trickery against the native village, whose members he holds responsible for his ape foster mother's death, Tarzan captures Rabba Kega, the local witch doctor, and puts him in a trap the natives have set to catch a lion. The next day the warriors find they have caught the lion, but it has killed the witch doctor. They take the lion to the village. Tarzan secretly releases it and appears among them dressed in the lionskin he had previously used to trick the apes. Dropping the disguise, he reveals himself and leaves. When the natives muster enough courage, they follow, only to encounter the real lion, which they assume is Tarzan in his disguise again. They are quickly disabused.

Tarzan Rescues the Moon

Tarzan frees a native warrior the apes have caught on being impressed by the man's bravery, angering the rest of the ape tribe. Alienated, he exiles himself to his parents' cabin. Later, frightened by an eclipse in which darkness appears to devour the moon, they summon him back. Tarzan reassures them by shooting arrows at the "devourer," and as the eclipse passes is given credit by the creatures for the "rescue."