Iron Winter. Book 3, Northland

The final volume in the millennia-spanning trilogy about an England with a very different history to our ownMany generations ago the Wall was first built to hold back the sea. Northland, a country of fertile plains and ancient forests rescued from the ocean, has become a thriving civilisation based on trade, technology and tradition, centred on the ancient home of the first builders, Etxelur. The whole of Europe, spanned by the Northlanders' steam caravan lines, has been changed in ways that could never have been predicted.
But nothing can last forever, not even the Wall. The weather is changing, growing colder, and in the wake of the long winters come famine, destruction and terror. And as whole nations are forced out of their lands and head for warmer climes, it seems that even Northland may not be able to endure.