A year after their sister Melanie mysteriously disappeared, Clover and her friends travel to the remote valley where she disappeared, searching for answers. While exploring an abandoned visitor center, they are stalked by a masked killer and gruesomely murdered one by one… only to wake up earlier that same evening. 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. Hoping it will fade, the group soon realizes that the number of remaining dead is limited, and the only way to escape is to survive until dawn.