前一波的食人鱼攻击终于画上了终点，此时，科学家们惊恐的发现，搅得人们天翻地覆的食人鱼居然还是处在初级形态的幼崽，天知道等到它们长大之时，又会闹出什么乱子！ 上一次的惨剧给谢尔比（丹妮尔·帕娜贝克 Danielle Panabaker 饰）的心里留下了深深的阴影，当她得知叔叔要在某处建立大型的豪华水上乐园时，谢尔比感到了强烈的不安。果不其然，不靠谱的叔叔为了节省经费，直接引入了附近的湖水，就这样，一大波食人鱼也随之而来，对于它们来说，一场饕餮大餐即将开席。面对着惨叫哭号的人们，谢尔比内心强烈的正义感让她无法对此坐视不管，勇敢的她连同幸存的伙伴们展开了轰轰烈烈的救援活动。Having awoken from their spring break extravaganza at Lake Victoria, the swarm heads upstream where they look to make a meal out of Big Wet, a local water park where when it comes to fun, nobody does it wetter! Though they came to get wet, get loaded and get some, the staff and patrons get more than they bargained for when they must face the fiercest, most bloodthirsty piranhas yet. Lead by the strong-willed, studious Maddy and her friends, Barry and Kyle, the trio must dive in and take on these man-eating creatures using every ounce of their being but can they be stopped?
