Praised as "not only a gifted storyteller but also a master of speculative fiction" (Library Journal), bestselling author Stephen Baxter brings his epic Northland trilogy to a close as a once-thriving civilization faces winter without end....

Many generations ago, the Wall was built to hold back the sea. A simple dam, it grew into a vast linear city, home to scholars, builders, and merchants.

But now days are growing shorter, temperatures colder, and in the wake of long winters come famine, destruction, and terror. As a mass exodus to warmer climes threatens to fracture Northland, one man believes he can outwit the cold and even salvage some scraps of the great civilization-before interminable gloom settles over the land; before the fires of war lay waste to an empire; before the ice comes....