With the arrival of the annual spring break, college students from all over the country flock to the resort of Lake Victoria, singing and dancing and having fun. Young Jack Foster (Stephen R. McQueen Steven R. McQueen) follows his friend to the seaside. At the invitation of TV man Derek Jones, Jack and his favorite girl Kelly (Jessica Szohr Jessica Szohr) and other friends boarded Derek's yacht. In a quiet corner, the girls enjoy swimming and enjoying the good time, but do not know that the danger is slowly approaching. It turns out that the recent changes in the earth's crust at the bottom of the lake led to the return of a group of horrific piranha trapped by volcanic eruptions in prehistoric times, and they launched fierce attacks on defenseless humans. The beautiful and pleasant lake suddenly turned into a bloody and cruel practice ground.