Rise of the Arcadians

Can you survive?
It's the year 2122, seventy-two years after the Upheaval that changed the world. The Earth is nothing like it once was -- rivers became oceans, waters washed away sands and soil to leave jagged cliffs, earthquakes reformed mountain chains, climates grew cold, freezing northern lands, and technology was lost or without resources to continue.
Humanity struggles on. Farming and protecting the wall guarding civilized borders from cannibalistic outsiders called the Oceaners are the main priorities. One stone citadel full of armed forces stands outside the wall’s center. Two more stand at the northern and southern borders. But good men to fill them are scarce.
For reliable help and information, Darvid Squire, leader of the citadels, relies on Scout, a nomad girl he met in the wild lands outside the wall. She knows much about humanity’s past and she knows things of the future before they happen. She also knows the secrets of the haunted outer lands everyone else fears.
When Oceaners band their forces to unconquerable numbers, the citadel leader is taken captive, and Desire with her knowledge along with a new recruit who has secrets of his own become humanity's last hope to stop the devouring and torture of the remaining world.