The Twilight Zone - The Bewitchin' Pool

Told by their parents that they are getting a divorce, Sport and Jeb Sharewood now have to decide who they are going to live with. They decide they would rather live with Aunt T, the woman they've met by traveling through a portal at the bottom of their swimming pool. Ar the other end is an idyllic world where children play and there are few adults. Aunt T is a kindly old woman but Sport is far more reluctant than Jeb to accept her invitation to stay with them.