It has been two hundred and fifty years since the planet was found, eighty seven years since the first colonies were established, and fifty years since the those colonies began to somewhat govern themselves. Its been 4 days since the supply runs stopped.
Now, the towns and villages are dealing with a breakdown of law and order. While many people try to stay within the laws as written, many have decided they are going to ignore it, and have turned to looting, and robbing. Others have decided that since there is no more outside influence, they can run the place themselves, and many have tried placing themselves above the law, no matter how much it may destroy them in the long run.
For no one is above the Law of the Desert.
Posters have turned up overnight in certain places, on them is a coded message, that if solved, gives instructions and explains the urgency of the state of things.
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To start, your character will be one such person who finds a poster, and solves it, and follows the instructions. The instructions tell the character to go to a certain place at a certain time for a gathering of people hoping to restore an order to the chaos.
This story takes place on a mostly desert planet whose surface has only ten percent water coverage, and is orbited by two moons. The planet also has a rotation of 26.5 hours.
The planet is in no way lifeless, it would have a variety of desert adapted plants and animals. The plants would resemble anything from tiny ground covers to huge trees scattered about the landscape, and the animals would be anywhere from tiny flies to surprisingly large herbivores, and the predators that eat them.
I took inspiration for the desert planet habitat from the spiny forests of Madagascar, the Deserts of the American west, the Australian Outback, and the Nile region of Egypt. The animals would somewhat resemble those of the Permian period on earth