New discoveries at mysterious Inca sites believed to be the home of legendary treasures reveal something darker: mummies that hold the secrets to this mighty civilization's fall. This episode is a mashup of S02E07, "Hidden City of the Incas" and S04E05, "Inca Apocalypse: the Dark Evidence."

The discovery of strange giant stone heads in the Mexican jungle leads archaeologists to La Venta, the lost capital city of the Olmec, and new investigations real evidence that the secret knowledge of these mysterious people changed life in the Americas forever.