Two sisters awaken one morning to blood red skies and the realization that the human race has been wiped out. It becomes apparent that anyone who was not surrounded by steel when the Earth recently passed through the tail of Haley’s comet has been reduced to a pile of red ash. They encounter a truck driver and take over the air waves at a local radio station in an attempt to get help but attract the attention of a group of scientists who knew of the comet and waiting to find survivors. They hid underground in a steel laboratory, but left the vents open. Now, as various survivors of the comet who were only partially surrounded by steel are decaying into flesh-hungry zombies, the scientists are attempting to create a vaccine made of the blood of people who were not infected by the comet while saving themselves at the same time.