Dick Sand is a fifteen-year-old boy that serves on the schooner Pilgrim, a whaler that normally voyages across the Pacific in their efforts to find targets. However, this time the hunting season has been unsuccessful, and as they plan to return home three people request passage to Valparaiso: Mrs Weldon, the wife of the hunting firm's owner, her five-year-old son Jack, his old nanny Nan and her cousin Bénédict, an entomologist. With not much of a choice, the captain accepts.Several days into their journey north-east, the Pilgrim encounters a shipwreck, with only five African-American survivors (Tom, Actéon, Austin, Bat and Hercule) plus a dog (Dingo), all of whom are brought into the ship and offered passage to America.It is as they get closer east that they encounter a whale, and the captain and crew decide to hunt it, in an attempt to make some profit off the season. Captain Hull reluctantly leaves Dick responsible for the ship in his absence while the rest of the crew approaches the whale on a smaller boat. However, the whale, while defending itself, destroys the boat and kills the crew, leaving Dick in charge of a ship with no experienced sailors to help him: only the shipwreck survivors are well enough to help him.However, the ship's cook, Negoro, has sinister plans for the ship: after breaking one of the ship's compasses and leaving them without a measuring device, he places a magnet on the other compass to trick the inexperienced crew into changing their route. In spite of the longer than expected travel, the group perseveres, and finally makes land, although the Pilgrim is lost. Negoro escapes with Mrs Weldon's money.A man called Harris meets the group and assures them they are in the Bolivian coast, encouraging them to follow him into the jungle, saying he can lead them to a nearby city. Dick begins to suspect that they are being lied to as they encounter several animals Harris insists are native, but do not seem to be like any he knows. It is as they hear a lion's roar and a horrorized Tom (who had been enslaved in his youth) finds several implements, that Dick realizes they are in Africa: Dick further learns, from eavesdropping into Harris, that they are in Angola, that Harris is Negoro's partner in crime, and that he was leading the group in to weaken them and make it easier for him to take Tom and the others into slavery.Dick and Tom's group decides to keep the truth from Mrs Weldon and her family, knowing that it will cause undue stress in them: instead, they tell Mrs Weldon that Harris lied to them, and Dick tries to lead the group to a river, which he hopes will allow them to reach the shore. A great storm leads the group to take refuge in a large ant nest, but the nest becomes flooded and the group barely manages to escape alive. This time, though, they encounter a group of slave traders led by Harris, who takes them prisoners: only Hercules and Dingo manage to escape, killing several traders and getting into the thicket to avoid detection. Dick, along with Tom, Bat, Actéon and Austin, is taken separate from Mrs Waldon's family, while Nan dies after a forced walk becomes too much for her.Both groups are taken to the lands of the king of Kazoonde, an old, petty king that trades with slave traders (among them Harris, Negoro and their chief, José Antonio Álvez) for European commodities. While Actéon, Austin, Bat and Tom are sold into slavery while none of the others can prevent it, Harris decides to taunt Dick by telling him Mrs Weldon, Jack and Bénédict have died as well: Dick answers by jumping on Harris and killing him with his own knife. Dick is made prisoner, to await his death. That night, however, the king (who drinks much alcohol, provided by Álvez) dies, burning alive, after he tries to drink flaming punch. The king's first wife takes over, and, in the subsequent funeral ceremony, nearly all of the king's wives, along with Dick Sand, are sacrificed.