Vanishing Trails is the continuation of the story of Daisy McLaren and Jake Smith told in Appalachian Trails: A Smoky Mountain Mystery. It picks them up again during the Fourth of July weekend of the following year. Daisy is living with her small calico cat named Rescue above her father's garage; Jake is living on the family farm.
Daisy still believes her mother had been murdered just before Daisy's graduation from UNC-Chapel Hill.
A young woman, Keira Swan, returns to Franklin after a long absence, and she has with her an infant. Before she can explain herself, she disappears in the middle of the night. Jake and his hound dog Susie Q track her to a spot down the road where Keira apparently got into a car to vanish.
When Daisy visits the trailers that the Swan family call home, she is knocked out and wakes up in her Jeep in front of an abandoned cabin high above the Cullasaja Gorge. When the county sheriff investigates, he finds the skeletal remains of eight persons, none of which could be Keira's. Secure in her belief that Keira might still be alive, Daisy continues her search for Keira and hopes that, by finding Keira, she might also learn why her mother died.