Earth is being held in the iron grip of a desperate and powerful alien race. They have herded the humans into camps and suppress any kind of resistance. Their race is afflicted by a terrible desease, one that will bring them to extinction if a cure is not found. A dorment gene in human DNA is needed for the cure. Actually, it is the most important element. However, it is incredibly rare, and only exists in 2 percent of the species. That is just enough, but it means that their search will be arduous and long, and when they are done, the human race will be a skeleton society, only hundreds remaining among their devestated planet.
It has been three decades since this began. Humanity has tried, but they cannot escape this fate. All hope is lost, and people just wait in their camps to die, fenced off and crammed into tight quarters. Once they are tested fully, whether or not the needed gene is extracted, the dead humans bodies are either tossed in piles and dissolved, or converted into weak, animated workers.
The sky itself has been altered, black and filthy with the clouds of millions of chemically dissolved corpses world wide. It is a depressing sight that only helps to keep the sheep down.
One young man, barely in his twenty second year, was born in one of these camps. His day has not yet come to be taken, but he is different. He has not been broken. He wants to rouse a rebellion, and no matter what his captors do to him, he will not be silenced. He will be made an example of, but nothing will break him. Even stranger, he continues to speak out even after horrible punishments. His legs being broken or jaw being dislodged are healed in days, and so his captors decide not to kill him.
He has the gene they are looking for. It is deformed. It has grown and adapted, and it is why he manages to survive and trudge on. After he is tested, he is returned to the cattle. They cannot harvest him yet.
Typical freeform story of a tiny spark of hope in a bleak future. There will most definitely be a secret rellion that adopts this guy as their flag. The game will start in the camp, and the first few chapters are going to be your struggle and the disciplinery actions of those who speak up or support this guy. You'll eventually break out and find this rebellion, freeing camps as you go, and try to drive this tyranny out.