Two hikers go missing along the Appalachian Trail, leaving only a bloodstained forest behind them, and when another hiker collapses on someone's porch in New Hampshire, murdered by crossbow, the local police realize they have a serial killer on their hands-and need to call in the FBI. FBI Agent Tara Mills is young, brilliant and new to the force. With a promising career in front of her, she faces the ultimate test when she is assigned the case. It soon proves to be more challenging than she ever could have imagined-an impossible riddle that leaves even her seasoned partner stumped. Meanwhile, something about the case stirs a darkness within her-a tortured past that even her long-term boyfriend doesn't fully understand. As nightmares consume her, she only hopes that her past will not come back to ruin her once again. As more hikers go missing, and with her job on the line, Tara finds herself on a race against time as she combs through the forest's trails. Peeling back each layer, she soon realizes that she is up against a true diabolical mastermind. And just when she thinks she has it all figured out, her instincts lead her to the most shocking truth of all.