The crowning volume of the trilogy that began with The Sea of Trolls and continued with The Land of Silver Apples opens with a vicious tornado. (Odin on a Wild Hunt, as the young berserker Thorgil sees it.) The fields of Jack’s home village are devastated, the winter ahead looks bleak, and a monster—a draugr—has invaded the forest outside of town.      But in the hands of bestselling author Nan...