As winter bears down, a gang of settlers races for their lives

Casey Storm doesn’t know who the Shadow Riders are. He only knows that they want to kill him. A dozen men in black slickers set upon Casey as soon as he reaches Montana, chasing him across the freezing plains for reasons he can only guess at. They chase him until his horse dies and keep chasing him even after he tumbles to the ground. He escapes only by chance, tripping and falling into a hidden coulee. The Shadow Riders pass on—and a winter storm descends.

Thick snow falls as Casey staggers up to the covered wagon, begging for shelter. The inhabitants are also on the run from the Shadow Riders, who seem to have mistaken Casey for Stan Deveraux, the gunman who promised to lead the settlers to safety. They have six days to reach the fabled land known as Sundown—six days before their property is stolen, and they are left to die at the hands of the Shadow Riders.