On a remote island in Lake Superior, scientists struggle to solve the problem of xenotransplantation -- using animal tissue to replace failing human organs. Funded by the biotech firm Genada, Dr. Claus Rhumkorrf seeks to recreate the ancestor of all mammals.

By getting back to the root of our creation, Rhumkorrf hopes to create an animal with human internal organs. Rhumkorrf discovers the ancestor, but it is not the small, harmless creature he envisions. His genius gives birth to a fast-growing evil that nature eradicated 250 million years ago — an evil now on the loose, and very, very hungry.