A year after her sister Melanie mysteriously disappears, Clover and her friends travel to the remote valley where she disappeared in search of answers. Investigating an abandoned visitor center, they find themselves being stalked by a masked killer and brutally killing one after another... only to wake up and find themselves back at the beginning of the same evening. Trapped in the valley, they are forced to relive this nightmare again and again - only each time the deadly threat is different, each more terrifying than the previous one. Hope fades, and the group soon realizes that the number of deaths is limited, and the only way to escape is to live until dawn.