Four people on a backpacking trip in the Sierra Nevada have been drawn to the mountains for reasons as diverse as their own lives. When they start up a pristine mountain trail that hasn't been traveled in years, all they have to guide them is a hand-drawn map of a remote, mysterious place called Lost Canyon. At first the route offers all the freedom and exhilaration they'd hoped for. But when they stumble onto someone who doesn't want to be found, the group finds itself faced with a series of dangerous conflicts, moral dilemmas, confrontations with nature, and an all-out struggle for survival.