In a summer resort island, a woman goes swimming at night and is taken by a shark. The fact that there's a shark in the water goes unnoticed until a boy is devoured while on his raft in front of people, during a busy beach day. The sheriff (who is afraid of water and yet lives on an island), a scientist, and a fisherman hunt the shark and finally kill it. The sheriff survives, but in the movie the fisherman dies, and in the book the scientist and the fisherman die. No one really comes out ahead in this one.