A year after her sister Melanie mysteriously disappeared, Clover and her friends head to the remote valley where she disappeared in search of answers. As they explore an abandoned visitor center, they find themselves being stalked by a masked killer and murdered in horrific ways one by one… only to wake up and 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 more terrifying than the last. With hope fading, the group soon realizes they have a finite number of dead left, and the only way to escape is to survive until dawn.