In January of 1959, a group of 10 Russian college students set out on a hike in the Ural Mountains in Siberia on a journey of some 700 miles. One student, suffering health problems, had to turn back and end his hike early. But that proved to save his life because an unexplained tragedy occurred in which all nine remaining hikers were killed in potentially brutal and purposeful passion. The cause of death remains a mystery as historians have wondered for more than 60 years: what happened at Dyatlov Pass?