In August 1993, veteran hiking instructor Lyudmila Korovina led six young trainees into Siberia’s Khamar-Daban mountains. After good initial progress, the group was caught in days of freezing rain, leaving them soaked, cold, and exhausted. On August 6, during their descent from 2,396 meters, 23-year-old Alexander Krysin suddenly collapsed, bleeding from the eyes and mouth, convulsing, and dying within minutes. Korovina attempted to help but soon suffered the same symptoms and died. One by one...