From publisher blurb:
The convoy must fight for its life against the combined might of the Ragers and the few Living Dead not yet frozen by the early winter. Escaping and finding shelter from the heavy snow in a nearby cavern, the characters are soon attacked in renewed force.
Left with little choice if they are to stay alive, they head deeper and deeper into the treacherous depths of the cave system, eventually discovering an opening at the other end. Left now with no vehicles or supplies, in the stark cold of heavy snowfall, it becomes clear that if the creatures do not kill them soon, the weather will finish the job.