Soon following Anna's arrival, the wolf packs under observation begin to behave in oddly. The discovery of wolf scat containing alien DNA leads the group to believe that perhaps a wolf-dog hybrid has been introduced to the island.

But when a female member of the team is savaged, Anna realizes that something is seriously wrong. Now, what was once an idyllic refuge becomes a place of imminent danger. Without electricity or running water, and with temperatures hovering around zero, Anna must fight for her life!

Filled with the nail-biting suspense, richly-drawn characters, and gorgeous nature writing that are her hallmarks, Nevada Barr proves once again that she can hold her own with the A-list.