Finally settled on sci-fi, and the story has been completely revamped.
The story is set on Earth, one million years in the future. By this time, humanity has evolved into a new species known as Homo peritus, a physically and mentally superior race. H. peritus live in a medieval-esque society, with the grand civilization of Homo sapiens buried under greenery and rock.
Several months prior to the events of the story, an alien being arrives to take control of the world using its superior technology. It successfully sways multiple kingdoms under its influence, allowing it to mass a powerful force augmented by its technological prowess. As word spreads of the alien threat grows, a resistance movement is formed. Stealing tools, weapons and gadgetry from the alien's forces, the scholars of the resistance are able to study, learn and imitate some of its technology, giving them an advantage. This replicated technology spreads across the free societies, changing the fabric of their lives.