What would have been the bed of the North Sea is now Northland, a society of prosperous, literate and self-sufficient people. They live off the bounty of the land, an area created by the building of the Wall. It began as a simple dam, thousands of years ago. Now, inhabited from end to end, the Wall is a linear city stretching for hundreds of miles, and a wonder of the world.

For millennia, the Wall has also kept the growing empires of the Bronze Age at bay. But decades of drought have destabilized those eastern civilizations. Men — and women — filled with greed and ambition have now turned their eyes toward the fertile West. A new and turbulent age is dawning. For any wall, no matter how strong, can be breached — particularly from within…