Joam Garral of Iquitos, Peru, concedes to his daughter’s wishes to travel to Belem, Brazil where she can marry Manuel Valdez in the presence of Manuel’s invalid mother. The Garrals plan to make the journey to Belem down the Amazon River, via a giant raft. Along the way, Joam plans to get his good name restored, as he is still wanted in Brazil for a crime he did not commit. Absolute proof of Joam’s innocence lies in the hands of a scoundrel named Torres, who has a cryptogram that will exonerate Garral. However, the price that Torres wants for this information is much too high.