One year after the mysterious disappearance of her sister Melanie, Clover and her friends head to the remote valley where she vanished in search of answers. While exploring an abandoned visitor center, they are stalked by a masked killer and gruesomely murdered one by one… only to wake up to find themselves back at the beginning of the same night. Trapped in the valley, they are forced to relive the nightmare over and over again, only each time the killer’s threat is different, each time more terrifying than the last. Hope fades and the group soon realizes they only have a limited number of kills left to make and the only way to escape is to survive until dawn.