While the hot rodders and motorcyclists are having a rock-and-roll beach party, a barrel of radioactive material is unloaded from a passing ship, plunges to the bottom and splits against a jagged rock. A black liquid oozes out and covers a shapeless mass on the ocean floor, which suddenly moves and becomes an encrusted vicious monster. Soon there are several monsters and they must have human blood to survive. Tina is the first victim, and football hero Hank Green and airhead Elaine Gavin enlist the aid of her science-professor father, Dr. Gavin, to solve and capture the killer. Not working fast enough to prevent the attack on twenty teen-agers at a slumber party nor the killing of three girl motorists, Dr. Gavin finds an arm lost by one of the monsters and discovers that only sodium will destroy the monsters whose composition is mostly water. Can they gather enough salt in southern California to put an end to this horror

　　佩姬是位美丽的艺术家，为了专心创作，她独自在外租了间公寓，在公寓的衣柜里，她发现一块占卜板，藉由此占卜板，前任房客苏珊竟阴阳连线上了。苏珊表示她是在这个房子内被杀死的，由于对此灵异事件异常好奇，佩姬每晚都玩起了占卜板，而她不知此举正释放出她无法控制的恶灵，而随著公寓内的房东夫妇惨死，佩姬明了只有她自己能阻止这场恶梦蔓延下去，但代价可能是她自己的灵魂。