In a distant future, dark due to all cities being built in layers, with the sun being something many rarely get to feel warm their pale sickly skin, live over a trillion people in the entire world. Birth control and sex education were abandoned claiming they were ruining the youth, and were deemed immoral. The population drastically rose with each generation, more ignorant and naĂŻve then the last.
People are separated by the layers of their cities, with thick floors of concrete, rebar, and steel girders keeping the different classes of society apart from one another. On the top are the one percentile, and those just below them, mostly middle management and right hand men/women. In the middle are what remains of the middle class, with resources and jobs becoming so scarce and spread thin, they can only hope to find work in the constant excavation and construction of the layers, getting only a bare minimum of necessary sunlight so they don't keel over out of lack of Vitamin D. For those that live at the very bottom, society mostly tries to ignore them, even though they are right under their feet, these people do not live down here by choice, anyone who cannot afford housing on the other two levels is forced down here, fitting that the darkest corners are where society places the things it wants to hide most...
Of course when you cram people together, with scarce resources, those people will try their best to survive, and some times the best way to survive will lead them to break the law. The judicial system had not laxed any as overpopulation got more and more out of hand, many people had seen it as a cushy alternative to being run down to the bottom layer. This drove the tax payers to riot and cause a reform in how prisoners are handled, loosening the requirements to be charged with the death penalty, causing the list of death row to become longer then ever imaginable.
But suddenly one day scientists had noticed a sudden and very drastic change in barometric pressure in five separate locations. Multiple countries had sent out groups to scout these locations out and study further, oddly enough it wasn't only barometric pressure that was off at these locations, gravity had seemed to be slightly lighter in the area. Studying this anomaly to try and use it in their research for artificial gravity, thinking they could use this to aid their over population by colonizing other celestial bodies. During their research, the anomalies had suddenly started producing sparks and loud sounds of thunder from a huge amount of friction occurring in the area. Then merely hours after the anomaly had progressed to this stage, it had opened up a spatial rift, fragmenting light all around it, surrounded in rushing streams of rainbow lights, the center of the rift pouring out fog.
After determining the rifts would be safe for living beings to enter, countries had sent in soldiers, trained astronauts, researchers, anyone that could potentially survive what might be at the other end of this rift. They were eager to use whatever was on the other end of this rift to offset its population issues, after extensive research and testing, they had found their solution. They had begun taking death row inmates, and indiscriminately sending them through the rift, under the condition that if they could live in this new world and work off what they owe to society. Little did these prisoners know the sad implications of what was really happening with these rifts...