One step too far / Lisa Gardner.

Timothy O'Day disappeared during his bachelor party campout in Shoshone National Forest. Five years later, he's still missing. But his father Martin has been searching constantly for him, even though it's now a hunt for a body. Tim's mother Patrice, is dying of cancer, and wants to be buried next to her son. Frankie Elkin is an average middle-aged woman - not a detective, or private investigator. But finding missing people is what she does. When the police have given up, when the public no longer remembers, she starts looking. Now she joins a motley crew - Martin, Tim's friends from that night, a search-dog handler, a local guide, and a Bigfoot hunter - in the latest attempt to locate Tim's remains. But as they head into the forest, what they don't know is that they are putting their own lives on the line...

Adult.