1914. Brazil's Rio da Dúvida, the River of Doubt. Theodore Roosevelt, his son Kermit, and the other members of the now-ravaged Roosevelt-Rondon scientific expedition are traveling deeper and deeper into the jungle to chart an unexplored river in the heart of the wild Amazon. Fighting off malaria and running short of food, Kermit and Teddy break with the group to hunt a long-overdue meal and are kidnapped by a tribe of cannibals: the Cinta Larga. In exchange for their freedom, father and son must find and kill a never-before-seen beast that plagues the tribe. A beast so ferocious it leaves only a shell of its prey behind. But what are the origins of this beast, and how do they escape its brutal wrath? Roosevelt's Beast is a story of the impossible things that become possible when civilization is miles away, when the mind plays tricks on itself, and when old family secrets refuse to stay buried.