The Alfred Hitchcock Hour S03E02 - Change of Address

Keith Hollands finds a beach house for lease, but Elsa, his wife, hates it because she's never liked the beach. Nevertheless, Keith rents the place and tries to convince the owner of the property to sell. Elsa spies a beautiful young lady named Rachel strolling in the surf, unaware that Rachel is the object of her husband's desire. Keith digs a trench in the cellar, ostensibly to eliminate dampness. Soon, three policemen arrive....