21 August, 2019...Cape Canaveral...

'-and lift off! Lift off of Explorer seven, NASA's first atmospheric sample return probe to Venus!'....

Venus had been born from the same cloud of star dust as its near neighbour and had been hit by clouds of debris left over from the birth of the solar system; but Venus had been hit harder than Earth and her rotation had been slowed to a crawl...on its surface, oceans grew and for a few fleeting millions of years Venus had begun the same road to life as her sister world.

But Venus was so much closer to the inferno that is the Sun..the great oceans began to evaporate, until eventually huge clouds of water vapour hung like a death shroud high above her surface; temperatures rose, pressure increased and the foul vapours from her volcanoes added to the clouds already high in the atmosphere.

And yet, life persisted; a micro organism that rose into the air along with the vapour of the oceans that gave it life. For millions upon millions of years it clung to life, living in a kind of stasis without oxygen to let it breed and evolve.

Then a new visitor arrived; visitors had come before, but they had always continued down to the hell below the clouds, or orbited Venus, probing her secrets; but this one flew through the clouds, scooping up some of the air as it went; then it fired it's engines and soared back out into open space, changing it's course and heading back whence it came, the blue, living earth.

In the sealed canister within the probe, the organism cooled and began to emit radiation; as the probe neared Earth, NASA control detected the emissions, and the decision was made to destroy the probe and it's cargo before it could enter the Earth's atmosphere. But the scientists had left it far too late; the probe exploded in a silent flowering of destruction on the very edge of the atmosphere... some of the organism survived and drifted down into the thicker air far below. Finding it rich with oxygen, it began thrive and multiply, each cell of each organism dividing at a frightening rate...every few minutes it reproduced. It took very little time for Earth's air to be filled with it.

The organism was inhaled by all that lived upon the Earth...Plants rejected it at once, animals likewise, their immune systems recognizing this alien intruder and eliminating it. But due to some quirk of human bio-chemistry, the bodies of people accepted the organism and took no action against it. The organism bred and settled into it's new living hosts, doing no harm, just wanting to live. Soon, every person on Earth was carrying the organism.

This would have been the end of matters but for one fact that was to change the World forever; when people died of accidents, violence or natural causes, the organism, deprived of oxygen again, would begin to emit radiation; this stimulated the nervous systems and the mind of the recently deceased, causing them to re-animate... the person they had been was gone, their memories, life skills and everything but the most basic instincts erased. Rumours began on the internet of people who had returned to life and attacked anyone nearby, biting them, clawing them, ripping chunks of flesh from their warm living bodies and greedily eating it.

The organism carried inside a victim would begin to change again, emitting its radiation. This attacked all the organs in the victim's body, specifically the renal and respiratory systems; they would die within 24 to 48 hours, then re-animate and attack more people. Then their came news reports of apparently random attacks on people; the authorities in most nations tried to clamp down on the news; they were unable and ill equipped to deal with what they were facing.

This continues for some weeks, the amount of victims and re-animates increasing until the critical mass required to interfere with the functioning of organized society was reached.

The apocalypse had begun.