The annual spring break is here, and college students from all over the country are flocking to the resort of Lake Victoria. They are singing and dancing and having fun. Young Jack Foster (Steven R. McQueen) followed his friends to the beach. At the invitation of TV man Derek Jones, Jack and his favorite girl Kelly (Jessica Szohr) and other friends boarded Derek's yacht. In a quiet corner, the girls swam and enjoyed a good time, but they didn't know that danger was slowly approaching. It turned out that the crust at the bottom of the lake had changed recently, and a group of terrifying piranhas that were trapped at the bottom of the lake due to volcanic eruptions in prehistoric times returned to the world, and they launched fierce attacks on unsuspecting humans. The beautiful and pleasant lake instantly turned into a bloody and cruel Shura field...