Many years ago the world was struck by enormous catastrophe. Nanobots that were used in many different industries got out of control at some point. They was growing in the earth like mycelium. And after that they broke through to the surface trying to entangle any organic.
All who can be saved did it immediately. Some of them flew into the cosmos, the second group built settlements floating in the stratosphere, others gone under water. But there were those who stayed and didn’t break the connection with the surface of the earth. They are in constant motion so that the nanobots couldn’t assimilate them. The large mobile city-arks was built using primitive technologies and without using nano bots. The cities one by one launched nuclear engines and started their own way that doesn’t have a final destination. In this game combing a strategy and RPG elements your should control one of such cities. Civilization fell, sophisticated technologies are forgotten and available resources are decreasing. That’s why you should hunt for the settlements to disassemble them for the parts and use for own development.