From the website:
A long time ago, far far away, a Queendom was overrun with thousands of pesky unicorns, relieving themselves on private property, eating endangered plant life and subsequently farting a lot! As unicorn gas is toxic, air pollution in the Queendom drastically increased, seriously impacting the local environment. This contamination created microclimates around the Queendom: it started raining sugar and candy, making everything sticky.
The good old Queen knew that unicorns had to be dealt with. Too kind to take action herself, she left the matter with her spoiled and selfish daughter, the Princess. Eager to show citizens that their princess was able to take action, she and her team of misfits would catch, and kill all the unicorns! She declared that four days each year would be dedicated to hunting unicorns, and everyone was invited!
This was great news for the Gnomes, who ran an illegal unicorn trade, a global black market for unicorn parts. This annual hunt meant they didn’t have to waste time catching the beasts themselves - a difficult thing to do - and could instead buy them cheaply from the citizens!