The Heart of What Was Lost (Osten Ard)

"Takes place in the half-year after the end of To Green Angel Tower, and tells of the attempt by Isgrimnur and a force largely made up of Rimmersgard soldiers to destroy the remaining Norns as they flee back to their homeland and their mountain. It also answers some questions about what actually happened in the immediate aftermath of the fall of Green Angel Tower"--Goodreads.com.