Professor Jacob Caine and his archaeology team are racing to excavate Ghost Bog, a 7,000-year-old bison kill site in northern Wisconsin, before winter arrives. Sam Noggle, Jake's old mentor, is assisting, excited to investigate this amazing site. Locals from the nearby town of Scenic are frequent visitors, eager to see the latest finds. Volunteer digger Pam Hauser uncovers an ancient human skeleton among the bison remains. Another human skeleton is then found, but wearing a modern-day watch emblazoned with the Scenic town logo!

The slain body of Matthew Walker, a rival scientist intent on taking control of the site, is discovered not far from Ghost Bog. The local authorities arrest Sam for Walker's murder and attempt to close down the dig. Unsure whom to trust, Jake and Pam decide to track down the killer themselves. Stymied as all the suspects have apparently solid alibis, Jake turns his attention to the watch-wearing skeleton found at Ghost Bog. Could "John Doe" hold the clues he needs to solve both murders?