This season, Josh Gates connects with innovative researchers and uses cutting-edge technology to tackle history's most challenging mysteries. The search for answers - and adventure - will take him into the most extreme climates on the planet, as he braves sub-zero temperatures to snowmobile across the Siberian Tundra investigating one of the coldest cases of the Cold War: the baffling deaths of nine hikers on Russia's infamous Dead Mountain. Josh also takes on the scorching heat of the Negev Desert as he descends into newly discovered caves and tunnels that could hold the next Dead Sea Scrolls. In addition, Gates dives into the waters of Panama and the mysteries of Sir Frances Drake's lost fortune. And, bushwhacking into the rainforest of Puerto Rico, Josh pushes his limits (and the boundaries of science) to explain the infamous cryptid, the Chupacabra.