The men huddled in their blankets against the hard-driving snow of the upper Sierra Mountains. They’d gone as far as human endurance would allow and farther than intelligence would dictate. They were stranded in the worst snowstorm in memory – their mules dead, their supplies diminishing. For a month they had fought the snows and winds, and temperatures so low the mercury never rose from the thermometer bulb. It was John Fremont’s fourth expedition into the West and it had become a disaster. His men were dying. It was Christmas. In the numbness of the moment, Fremont decided his party could not go on. The blizzard howled about them as they began their retreat, with bleeding feet, frostbitten hands and faces, and snowblinded eyes. But death started back with them.