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