Relates the saga of the Expedition — led by Rondon and the ex-president of the United States, Theodore Roosevelt — which crossed Pantanal and the Amazon Forest to explore the River of Doubt. The tale is told through dramatisations, archives from the American Congress library, Civelli Memorial archive, indigenous testemonies of the Pareci, Nhambiquara, Sabanê and Cinta-Larga peoples, and Marechal Rondon's granddaughters. A century later, they comment the journey, exposing different worldviews, discussing the environment, indigenist policy and Amazon development.