Na Rio de la Plati

The protagonist, a nameless German traveler (occasionally called Charley, implying a connection to Old Shatterhand), arrives in Montevideo bearing a letter for Señor Tupido. He accidentally discovers that the letter is part of a plan to supply weapons to the rebel Lopez Jordan. Because of his resemblance to Colonel Latorre, he gets drawn into a series of conflicts and identity swaps.

The journey takes him through the pampas and forests towards Gran Chaco, in search of the mysterious Inca treasure, associated with the quipu (knotted writing) and the enigmatic Sendador Geronimo Sabuc. With him are allies such as yerbater Mauricio Montes, brother Jaguar and sailor Frick Turnerstick. The story is full of conflicts with Jordan's pains, raids, escapes and moral dilemmas, with May's characteristic emphasis on justice and non-violence. The novel exudes vivid descriptions of South American nature and culture, although May never visited those parts.