The lake country straddling the Kentucky-Tennessee border has a quiet, majestic beauty. But in September 2022, that vast landscape seemed to have swallowed up Mike Harding, a California transplant who disappeared without a trace.

JULIE HARDING (phone call): Hi Captain, this is Julie Harding with the California Highway Patrol …

Mike's wife Julie Harding, a captain with the California Highway Patrol, began to place urgent phone calls to the Kentucky State Police from her home in Sacramento.

JULIE HARDING (phone call): I can't get any information. And I just, I need your help with this … My concern right now … is where he is. Is he OK? … and what's the status of this investigation?

The calls led her to a sheriff she knew — Brandon Boone of Clay County, Tennessee, whose office was spearheading the missing person's case.…