Historian John Keller was at a conference in one of the Swiss hotels when nuclear weapons destroyed much of the world. People are gripped by panic. But John remains faithful to his profession and documents events after the catastrophe, compiling a chronicle of the days unfolding around him. He carefully records his own experience and also gathers stories from other guests, hoping he can preserve at least the memory of the disappearing humanity. But many of those still alive have their own secrets that they are not ready to share…
John finds the body of a small girl on the roof. Who among the guests is the killer? Keller begins to investigate the huge hotel, hoping to find the culprit and answers to his questions.