Every 40 seconds, a person goes missing. In northern Idaho, a group of teenage girls attend a summer camp to help them connect with nature - without technology. They're told it will be a summer of change. When the girls' houseboat is suddenly stranded in the middle of a river, an odd couple comes to their aid. But what's supposed to be an act of kindness turns deadly and the girls find themselves on the run, pursued through the forest by a brutal, determined killer.