73 A.D.—AFTER DEATH, THAT IS.
Somewhere on the crumbling road between the Palisades Enclave in California and the remains of the Chicago Spaceport, a brightly-painted wagon rumbles along on the last rubber tires in the world. Mordecai Lehrer is moving east. His wagon is a traveling medicine show, a peddler's pack, home from part-time magicians—and a courier service for Earth's last enclaves of scientific knowledge. Ninety per cent of Earth's population perished in the Death, and the remaining ten blame the evils of godless science for that terrible plague. They would destroy the science-enclaves if they could—and they grow bolder day by day.
But the enclaves know what the people cannot: scientists in the Mars colony have discovered that the plague will inevitably be followed by a mutant form virulent enough to wipe out all of the survivors of the first siege. Mars has also found a vaccine, and even now a suicidal mission of mercy is racing toward the ruins of the Chicago Spaceport.
Meanwhile Mordecai Lehrer bumps across the plains of the west, carrying precious instructions from the California enclave on how to grow and use the vaccine. He travels in secret, and in fear, for all around him are the people whose lives will be saved if he succeeds—and who would kill him gladly to ensure his failure.
This two minutes of test tape is brought to you by the planet Mars 123456789 message follows message follows
"Our continuing research into the mutated ECHO virus that is responsible for the disease known as the Death shows the existence of a secondary mutation, which has a fifty per cent chance of occurring spontaneously within a hundred thousand generations. This new form of the virus is invariably fatal to all tested rodents and primates, even those immune to the primary form. It does not affect dogs, cats, or cattle. It has not been tested on humans. Statistical analysis indicates that if, as is probable, it is also fatal to humans, the population base of Earth is still large enough to support a pandemic. This would, effectively, destroy what remains of civilization and ninety to ninety-five per cent of humanity.
"According to our best available models, the pandemic will occur at an originating site in North America or Europe in not less than twenty or more than thirty years