Count Hamnet Thyssen is a minor noble of the drowsy old Raumsdalian Empire. Its capital city, Nidaros, began as a mammoth hunters' camp at the edge of the great Glacier. But that was centuries ago, and as everyone knows, it's the nature of the great Glacier to withdraw a few feet every year. Now Nidaros is an old and many-spired city; and though they still feel the breath of the great Glacier in every winter's winds, the ice cap itself has retreated beyond the horizon. Trasamund, a clan chief of the mammoth-herding Bizogots, the next tribe north, has come to town with strange news. A narrow gap has opened in what they'd always thought was an endless and impregnable wall of ice. The great Glacier does not go on forever--and on its other side are new lands, new animals, and possibly new people.