Synopsis Jonathan Sheppard, a pilot and aeronautical specialist with Boeing Inc. in Seattle is invited to Washington by the Department of National Defense to present his work on new alloys developed in his laboratory. He arrives several hours early at the airport and is able to change to an earlier plane, flight 684, leaving almost immediately. Once on board, he checks his e-mail and finds an urgent message from the Department of National Defense. He contacts Gerald, at National Defense Headquarters, who is surprised and concerned that Jonathan took an alternative flight to the one they arranged for him. Their concerns appear to be related to the incidents of earthquakes occurring with increasing regularity around the globe. Jonathan dozes off and is rudely awoken to witness the devastation occurring in Minneapolis. He is contacted by the National Defense that informs him that the earth is undergoing considerable unrest as a result of nuclear tests combined with the depletion of resource basins of oil and water. This destabilized the planet causing a shift in the earth's orbit with considerable activity in the inner core. The plane that he was originally scheduled to take was specially designed to take him and other scientists to space platforms located sixty thousand feet above the earth. As a result, flight 684 will have to rendezvous with one of these planes in Winnipeg, Canada. The plane changes course to Winnipeg, but the pilot is informed en route that the very heavy demands worldwide won't make a plane available for some time. National Defense suggests they refuel in Winnipeg and then fly on to Whitehorse in the Yukon to rendezvous with one of their planes. During the flight, Jonathan befriends Karen Grace, an attractive stewardess, who is very distressed as her family lived in the now devastated city of Minneapolis. During refueling, a major earthquake hits Winnipeg which necessitates the plane leaving only partially refueled. The remainder of the book deals with a series of adventures in which flight 684 makes a number of unscheduled stops before making its way to Whitehorse. Jonathan and Karen become very close and soon learn about government plans, going as far back as the early sixties, designed to develop strategies for saving the human race should a cataclysmic event occur. These include the development of Cities of Refuge, as well as space stations and space platforms. On the final flight to Whitehorse, flight 684 suddenly finds itself in the middle of a terrible storm. One of the engines catches fire resulting in it crashing some thirty miles from Whitehorse. The final section deals with the trials and tribulations of surviving in the frozen wilderness, including being attacked by wolves, until they finally board the specially designed plane which takes them to one of the space platforms.