A year after their sister Melanie mysteriously disappeared, Clover and her friends head to the remote valley where she disappeared in search of answers. Exploring an abandoned visitor center, they find themselves stalked by a masked killer and gruesomely murdered one by one… only to wake up to find themselves again at the start of the same evening. Trapped in the valley, they are forced to relive the nightmare over and over again, only each time the killer threat is different, each more terrifying than the last. With all hope now lost, the group soon realizes that the number of dead is limited and the only way to escape is to survive until dawn.