Scientists and anthropologists study the ancient craft of head shrinking and the troubled culture of the Shuar, the indigenous tribe in Peru and Ecuador that made them. In the 1840s, Western explorers entered the Amazon rainforest and stumbled upon the ancient ritual of head shrinking. This isolated ceremonial practice soon became an obsession to trophy collectors, setting off a bizarre international trade, and a deadly new chapter in the history of the Shuar tribe. Follow a team of anthropologists, historians, and scientists as they use DNA, forensic science, and computer modeling to examine the ancient craft of head shrinking and the story of a society of victims, who were also perpetrators.