Jaws is a tense thriller, with a terrifying final act where Brody and a small crew come face to face with a killer great white shark. Jaws opens with a scene where a young woman goes into the ocean to swim, but she is soon pulled under the water and disappears. The following morning, police chief Martin Brody learns that the incident was a result of a shark attack, and he chooses to close the beach in order to do a further investigation and eliminate the threat.

https://screenrant.com/jaws-movie-ending-explained/