This is the final book in the Northland saga.The glaciers have returned, and the Northlanders world is being gripped by ice. Mass migration bring forth war between nations, and plague kills those that the cold does not get.Rina and her children travel from Northland to warmer climes, and she finds there that the status she enjoyed is nothing no, and she works as a simple servant, her sone in the army, and her daughter offering care to the plague victims. Pyxaes, an uncle, is one of the sharpest minds of his generation, and he understands the reason why the ice has returned, and travels to the Khan of the Steppes to meet with other scholars to compare theories. He returns with a secret that can bring devastation, but also peace to the warring nations.This is the most dramatic book in the series, and Baxter manages to convey the pain and suffering of once great nations as they battle over diminishing food sources. He has used advances in technology to give then steam power, and other details like the Roman empire still having some influence. The thing that annoyed me slightly is the gaps between each of the previous books and this one. To me a sequence should have a link; I know that the wall is the common thing, but it would have been nice to know that people were linked as well.