The world as we know it no longer exists. Twenty people are trapped in a hotel. One of them is a murderer.

Historian Jon Keller was in Switzerland when the nuclear attacks brought the world to an end. As civilization slowly sank into darkness, he wondered if his wife and two children were all right, but he missed his chance to find out. There were twenty survivors in the hotel where Jon was staying. They were far from the city and had nothing to do but wait and try to survive. Then a body was found; apparently one of the twenty had committed murder.