Nelson, investigating a series of murder-suicides he has connected to an archaeological discovery -- and to Ruth's seemingly sweet new neighbor, Zoe -- he enlists Ruth's help until she, Zoe, and Kate go missing and he is left scrambling to find them before it's too late.

When an old college roommate invites Claire Britten to join her on an archaeological dig at a Florida peat bog, it's an offer the renowned forensic psychologist can't refuse. Claire's husband, criminal lawyer Nick Markwood, is comforted to see Claire working on a prehistoric burial site instead of an open grave for once. But Claire's investigative instincts kick in when some of The Black Bog's perfectly preserved corpses show signs of a grisly fate....