Every year Scott Robertson, a generally admired Yale student, and his screw-up mate C.J. Longhammer from Minnesota cross the Wisconsin border for a wild night. Scott has a girl in his Saab, but as usual must return to the bar as CJ started a fight and this time Scotts adoring kid brother Robbie is with them, and just was about to lose his tormenting virginity. Scotts fists get them out. They are followed by a black Cadillac, make a risky drive on the lake to shake it, allow Robbie to take an urgent leak and give a lift to a neighboring sheriff, Charlie, who has car trouble in Arctic weather. The Cadillac keeps following and even ramming them, so they start wondering why and suspecting each-other, and it gets worse...