A year after her sister Melanie mysteriously disappeared, Clover and her friends travel to the remote valley where she disappeared in search of answers. While exploring an abandoned visitor center, they find themselves being chased by a masked killer and brutally murdered one by one...only to wake up the same night to find themselves earlier. Trapped in the valley, they are forced to relive the nightmare over and over again, only each time the threat of the killer is different, each time more terrifying than the last. As hope dwindles, the group quickly realizes that they have a limited number of dead left and the only way to escape is to survive until dawn.