The wife of a well to do dentist is on the verge of having an affair with Peter Trilby, also a dentist. They get a few hours to themselves just before her son comes home from school. But the husband comes home unexpectedly and them discovers in the bedroom. He is furious, and challenges Peter to a duel. Eventually, the wife is saved, and Peter, having bowed out, goes down to the school to pick up her son.