To celebrate passing the exam, seven students from Tulane University, including Nick (Dustin Milligan), Gordon (Joel David Moore), Beth (Katharine McPhee), Merrick (Sinqua Walls), Maya (Alyssa Diaz), and Sabine (Donal Logue), made an appointment to go on vacation to Lake Colosseum, the hometown of their classmate Sarah (Sara Paxton). The beautiful scenery, pleasant views, and the hospitality of the host made this trip full of joy and excitement. However, their youthful and romantic time did not last long. Merrick, who was an athlete, was attacked by an unknown creature while surfing on a motorboat and lost an arm. This accident seemed to foreshadow their future fate. No one would have thought that a man-eating shark in the calm lake was coveting these young men and women...