A year after her sister Melanie mysteriously disappeared, Clover and her friends head to the remote valley where she disappeared in search of answers. While exploring an abandoned visitor center, they find themselves being stalked by a masked killer, horribly murdered one by one… only to wake up to find themselves earlier that night. Trapped in the valley, they are forced to relive the nightmare over and over again, but each time the killer’s threat is different, each time more terrifying than the last. With hope fading, the group soon realizes that they have a finite number of dead left and that the only way to escape is to survive until dawn.