Five American boys traveling with their academy professor journey from New York to Venezuela, visiting coastal towns, Lake Maracaibo and the mighty Orinoco while exploring plantations, mines and the wide llanos. Their travels mix sightseeing with practical lessons about coffee, cocoa and local industry and with outdoor pursuits such as camping and hunting. The party encounters storms, river squalls, jungle hazards and wild animals—including a perilous run-in with a boa-constrictor—and at one point becomes lost in the interior before overcoming dangers and reuniting to complete their expedition.