One Dark Night tells the story of two lovers Tessa and Mike, that meet a mysterious stranger named Max at bar. Tess and Mike have had some financial problems and Max promises them a solution to their problems. Mike isn't interested, but Tessa takes the bait. Soon begins a descent into evil for both of them. Mike must run for his life to get away from a newly possessed Tessa after it appears that he killed her. To top things off Joey (her little brother) thinks Mike has killed her and is hot on his trail too. Soon enough Joey confronts Mike and realizes that he too has become part of the "circle".