Penny, a young woman traumatized by a childhood car accident that killed her parents, accompanies her therapist on a road trip back to the scene of the accident as part of her therapy to overcome her fear of cars. But, when the two women accidentally cross paths with a dark and mysterious hitchhiker on a lonely stretch of mountain highway, an attempt at healing suddenly takes a terrifying detour into a horrific life-and-death struggle with a ruthless, deranged killer, bent on preying upon Penny's worst fears.