Alfred Hitchcock Presents S05E26 - Mother, May I Go Out to Swim?

John Crane is a mother's boy. He goes to Vermont and falls in love with Lotte Rank. They decide to get married. Later, John's mother, Claire, arrives. She obviously dislikes Lotte and John is reluctant to tell her that they want to marry. Lotte and John plan to kill Claire. They take her up to a cliff, but John has a change of heart. He shoves someone to her death, but it is not his mother; it's Lotte.