Karova, a Guarani abandoned as a child and raised by Jesuit priests, hears that in his homeland, Yguazú, there is a secret treasure that could change the life of anyone who finds it. He decides to go after that treasure, but his homeland is far away, and to get there he must overcome mighty rivers, a vast jungle, and also get permission from the strict religious fathers. His adventure begins when he eavesdrops on a private conversation of the religious, in which they comment that he is old enough to accompany Fathers Diego and Claudio, who are going to found a new town, Santa María del Yguazú, where he will live experiences never expected.