Jonas Plum is the name of the candid protagonist of this novel set in the Caribbean in the early nineteenth century. He tells the reader how his uncle and aunt rid themselves of him by putting him on a merchant ship bound for America and how he got lost in the jungle with Professor Clipercuff, who becomes his teacher and companion on his adventures. The two are captured by aboriginal cannibals and rescued by a rival tribe, the Arahuacos, with whom they live peacefully. Jonas falls in love with Vitali. However, on a trip to a neighbouring village, Jonas is kidnapped by a French officer, triggering another string of adventures. He crosses swords with pirates and fights a duel to the death from which he emerges victorious. He is made a count thanks to a powerful man on an island where he lives quietly until he is visited by the crew of Greenbeard the pirate, who want him to become their captain. Master of the “Nadie vivo” (no-one alive), he then decides to return a group of African slaves to their native land. On the way there, he manages to lay his hands on a rowboat and makes his way home. But the crew finds him and decides to abandon him on the island where he writes his memoirs.