White consumes the New Hampshire landscape, as US troops close like a platoon of ghosts on an armed cult, following a spate of unnaturally severe blizzards. Screams are carried on the frosty winds, but as the troops break in they find the house deserted. A gunfight with no victims. The Doctor, hoping to give Leela a taste of life among the tribes of Native America, finds he has fractionally misjudged his coordinates, and they too are trapped in the frozen wastes, for he has strangely lost his homing affinity with the TARDIS. In the nearby small town of Winnipesaukee, a little girl called Amber Mailloux, distressed by the disappearance of her father, frustrated with her mother's roaming, unsettled life, feels almost at one with the heartless, lonely raging of the storm. But none of them know that the snow, the ice is not just a backdrop, but the real enemy. At the heart of the drift is a living presence, glorying in the cold, inhuman structures of the ice. And it's hungry...