A year after her sister Melanie mysteriously vanishes, Clover and her friends head to the remote valley where she disappeared in search of answers. As they explore an abandoned visitor center, they are stalked by a masked killer and murdered one by one in horrific ways… only to wake up and find themselves back at the beginning of the same evening. Trapped in the valley, they are forced to relive the nightmare over and over again – only the murderous threat is different each time, each time more terrifying than the last. Hope fades, and the group soon realizes that the body count is limited and the only way out is to survive until dawn.