Introduction

They had fumigated the planet. Now it was just a matter of time. The gas had infiltrated the DNA of the species and accelerated the ageing process. Soon everything would be theirs.

They need not start from scratch. They would merely take over their technology, though primitive, it would be a new beginning for their race. The dominant species would seize to exist.
They need not do any clean-up as the species would bury itself, leaving behind everything intact.
They had no scruples doing what they did, they merely replaced an inferior race as it had always been done. Mankind was about becoming extinct.

When man noticed that he was ageing rapidly, it was too late. Totally unprepared for this onslaught the process was irreversible. With a month becoming years at a time, the population shrank rapidly. The newborn ones aged so fast that they never reached adulthood.
Preachers told the people to repent their sin, but there was no god and science had no solution.
Those who could have researched the causes, provided a solution, were buried long ago.
And the new settlers were waiting patiently.

In Research Station 5 the Moonies were staring at the TV, watching and listening.
The virus had not yet affected them, life seemed to be normal in the secluded station where humans were simulating living on a base on another planet. They had been there for more than three years listening to the horrifying news of people dying in masses, the chaos caused by a society falling apart, where the rule of law ceased to exist as man had no future, only today, and today alone, taking, doing whatever one pleased.
Unlike the other stations where the researchers had left for research centres to find a solution, just to be infected themselves, Station 5 had decided to stay put. Something was out there which infected the people, letting them grow old long before their time.
With their limited resources they had also tried to find the cause and a cure against the disease, but to date they had been unsuccessful.
They had watched their colleagues from Station 3 age uncontrollably after refusing them entry to Station 5 due to fear of infection, analysing their cells, finding nothing besides a minor pattern change in the DNA, a change they could not explain.
One after the other the news stations had fallen silent until only a humming was heard, indicating a sender, but no one to broadcast, until today. Suddenly a staccato of sounds. They listened, trying to analyse what was said, but to no avail. Then pictures, news clips flashing on the screen: aliens walking; aliens picking up human remains dumping them in bins; aliens clearing up the chaos in the cities, chaos created by the dying race; aliens using human technology.

Suddenly it dawned upon them: What if it was no accident, what if they had been exterminated like cockroaches? These two-legged four-armed aliens who were so human like, yet so different, were they claiming the spoils?

Unlike the Hollywood creations where spaceships destroyed everything, had they just removed mankind?
Were they at Station 5 the only human beings left?
With this realisation they switched off the Stations ping, making it almost invisible to outsiders.

Then a newsflash showing rounded up human beings. Unknown chattering commentary. And then showing the humans been taken to a zoo, sharing a cage next to the other primates, the gorillas.
Had the disease come to an end or were these people immune? The first seemed to be the case.

With the realisation that man had almost been eliminated by the aliens, a hatred came, a hatred filled with vengeance: they would destroy them, they had to destroy them!

As any armed resistance would merely have been a suicide mission, something else had to be done. The simplest way seemed to be to use the alien method: DNA manipulation. They did not know how to do it, but they had every intention finding out. And to do the research, they needed an alien to analyse it’s DNA.

And they had no scruples cutting this alien to pieces, catching more of them for tests. They watched photos of these aliens on TV and assumed that it was all about the missing ones. These Quads, as they called them because of their four arms, were just beasts anyway.

Finally they had a solution. It was not an overnight solution, but rather a long-term one.

As they had no means to gas the whole planet as the Quads had done, this alternative had a different approach:
In the first phase it would attack the intelligence of the Quads with a retro-gene change; the second change would lead to subsequent infertility in the following generation. Thus the capability of intelligent research by the Quads would be destroyed, eliminating their ability to solve the subsequent infertility problem. It would take time, but eventually they would just die out.
This creeping disease would catch them just as unexpectedly as their attack had caught the earthlings.
Nothing would indicate its existence until it would be too late. As to infecting them: what better way than by attaching it to their reproductive system, infecting them like venereal diseases had infected mankind over the centuries, highly contagious. The first dose smuggled into a vaccination against the common cold, which strongly affected the aliens, thereafter nature would run its course.
And if these Quads contacted their mother planet, the disease would spread. They deserved to die.

They were all aware that none of them would live to see the results, but they would eventually recolonise the earth, Station 5 being the arch for a new earth. What was needed now were new families with many, many children. ‚Go and multiply!‘, the old biblical command. There would be lots of space later, but for the time being they would have to stay in the safety of Station 5. And they were well prepared to live in seclusion.

As to the humans in the zoo, they could not help them. Perhaps the Quads treated them the same way as the humans did the monkeys in their zoo. In that case a new generation could free their offspring, who knows?