A mermaid called the Sea Lady visits an English family known as The Buntings; ostensibly to learn about the modern world. But her real goal is to initiate an affair with the handsome, charming, moderately wealthy young gentleman named Harry Chatteris. He is running for political office and has an extremely beautiful fiance: the religious and social propagandist Adeline Glendower. But his life is sterile consisting only of work and duty. The Sea Lady offers a departure into the Great Outside, “There are better dreams…” she says.