Lake Lucas is a place of tranquility. Known for its long trails, camping grounds, and fishing, it is a popular place for hikers, campers, and anyone looking to get away from society. For ex-con Valentine Krane, it is the perfect place to start fresh and new. Unfortunately, nature has other plans. When someone from his past is violently murdered in the lake, Valentine finds himself under suspicion. The police investigate him, oblivious to the real threat lurking under the tranquil water. Their search for answers reveals a series of strange occurrences. A camp is discovered on the shore, its occupants missing, the sand covered with blood; vacant fishing boats idly drift in shallow coves; and a tent is found shredded to ribbons. By the time they learn the truth, it may be too late. Radioactive crabs, equipped with razor-sharp claws that can tear through Kevlar, have infiltrated the lake. Hungry, ravenous, and without mercy, they seek to devour anything and anyone in their way. Anyone in the path of this crab attack is doomed to suffer a violent death.