When young couple Tom and Lucy lose their way while driving to a music festival in the remote Irish countryside, they find themselves trapped in a maze of back-roads with only their vehicle for protection, terrorized by an unseen tormentor hell-bent on exploiting their worst nightmares. Driving, lost and tormented in the night, primal anxieties of the dark and the unknown take hold as the couple realizes that they may have to let the evil in, or that it is already there.