Art Gundersen did not make it as an agent with the Bureau of Trans-Species Affairs. But when Chief Townsend orders him out of the lab and into the mountains of northern California to collect evidence from a murder scene, Art's happy to go. He looks forward to tromping around in the wilderness—and finds he enjoys the company of the forest technician who discovered the hiker's corpse surrounded by sasquatch footprints.
Jerry Humboldt lives a somewhat reclusive life in the fire lookout tower. Nobody comments much on his enormous size. Or his unusually hairy feet. Then Art shows up, and Jerry is forced into some new realizations.
As Art and Jerry interact, they discover some long-past connections as well as some very present dangers. It's a risky equation: an awkward not-agent, a virginal "wild man" of the forest, and a multiple murderer—with the Bureau's help six hundred miles away.
