A virus long ago escaped, infecting the whole human race, giving them an inability to have contact. Only once in their life may they have contact with the Non-Contacters without dieing, but that one time is wasted when they are born. How does the human race reproduce? Simple. Some are born immune to the virus. They are born with the Mark, showing the world that they are Touchable. And everyone, even the Non-Contacters, can touch the Touchables.
The Touchables, to keep the human race alive, are instantly imprisonned. They spent their whole life in an institute, until they are sixteen. They are given and sold to whoever the Goverment chooses. Scientists and geniuses in the most part, trying to create smarter and smarter children. But, they are also sold in secret. Sold for pleasure to rich Non-Contacters seeking sexual companions in the black market. Abused constantly, and forced to bear children. Unable to choose who they want to love, unable to fight back.
But the scientists are working on a cure, to make everyone Touchable again. Rumor is that they already found the cure, but the Goverment refuses to share it to keep the Touchable market going. Other rumors say that the cure makes you Touchable, but venomous. Able to reproduce, but killing your partner. Making them wither and die. A way to keep the growth of the population in the Goverment's hands, a way to kill their enemies. Pretending to send a Touchable, while instead sending a Venomous.
But those are just rumors.