One family and some friends try to run away in a sailboat, and the story describes their battles with nuclear winter and fallout, and with the ensuing collapse of civilization.
Scenarios based on theoretical calculations predict a long nuclear winter, as the radioactive waste will hang like a cloud in the earth's atmosphere and will absorb the sun's radiation.
The resulting war lasted only a few hours, but between the nuclear exchange and the years of nuclear winter that followed, the overwhelming majority of the human race was annihilated.
