Sam Westin is rarely afraid in the wilderness, but maybe she should be now. Her friends Kyla and Kim were murdered on a popular hiking trail only a few weeks ago and the murderer is still unidentified. When Sam steps in as a substitute for Kim to shepherd six troubled teens through the backcountry, she can't help watching over her shoulder. Has grief at the violent deaths of her friends made her paranoid, or is she right to suspect her rag-tag band is sharing the mountain wilderness with the killer?