In the times of Princess Platinum's rule, there was much uncertainty. Political squabble with the earth ponies and pegasus, rumor of dangerous black magic, and crimes against the crown even in the Marble City. Certain crimes were seen to be egregious but not punishable by death, but still quite severe. Mass theft, disloyalty, medical instability, and attempted murder to name a few. While these crimes were in need of punishment, funding kept the Platinum rule from keeping a large prison and they needed to be sent somewhere. So, the Princess started The Colony: a place for criminals to be sent to die. It kept the blood off the royalty's hooves, the gold in the Princess's pocket, and the public happy to see these criminals gone.
When Midnight Star is faced with the sentence of joining The Colony, she finds that not all things are as simple as they seem and that everything has a price.