This is the story of a young woman who works for the Pleistocene Project, an effort to transform the megafauna of a region of northern Alaska into what it was like during the late Pleistocene. This has become possible because large animals such as the woolly mammoth, woolly rhinoceros, and cave lion have been genetically resurrected using the DNA from bodies preserved in permafrost. These animals coexist along with other animals, including caribou, moose, and grizzly bears, still found in the region. The young woman is a member of a team of scientists who monitor and carry out research on this unique assemblage of ancient and present-day animals. Her encounters with some of the resurrected animals represent the primary story line of the book.