Paulvitch still lived and sought vengeance against Tarzan. As part of his plot, he lured Tarzan's young son away from London. But the boy escaped, with the aid of the great ape Akut, and they fled to the savage African jungles where Tarzan had been reared.There the civilized boy had to learn to meet the great beasts and face the dangers only his father had ever conquered. But he grew in time into Korak the Killer, almost as mighty as Tarzan. Korak found a friend in Meriem, whom he rescued from a raiding Arab band. Then he discovered that the dangers of the jungle were nothing compared to those devised by men.
The long boat of the Marjorie W. was floating down the broad Ugambi with ebb tide and current. Her crew were lazily enjoying this respite from the arduous labor of rowing up stream. Three miles below them lay the Marjorie W. herself, quite ready to sail so soon as they should have clambered aboard and swung the long boat to its davits. Presently the attention of every man was drawn from his dreaming or his gossiping to the northern bank of the river. There, screaming at them in a cracked falsetto and with skinny arms outstretched, stood a strange apparition of a man. "Wot the 'ell?" ejaculated one of the crew. "A white man!" muttered the mate, and then: "Man the oars, boys, and we'll just pull over an' see what he wants."