In February 1910, the Seattle Express passenger train is marooned by record snowfall in the Cascade Mountains of Washington State.  The snow falls faster than it can be removed, and despite the tireless efforts of the men of the Great Northern Railway, the train stays stranded for six days, until a massive avalanche knocks it off the tracks and down the side of a steep ravine in the middle of the night. In an age before radio, radar, or GPS tracking, rescuers must find the train and come to the aid of the survivors, before they too perish in the next avalanche.