Splash

In 1964, eight-year-old Allen Bauer and his family are taking a boat tour at Cape Cod, Massachusetts. Allen is fascinated by something below the surface and jumps overboard. In the ocean, he encounters a young girl and inexplicably finds himself able to breathe underwater. However, Allen is rescued and pulled back to the surface, and the two are separated. Since no one else saw the girl, Allen comes to believe the encounter was a hallucination.