When Anthony, Lord Crackenthorpe, an English entomologist, invites Mrs. O'Mara, the widow of an Irish zoology professor, and her daughter Peggy to live on his estate while they collaborate on a study of the spider, he incurs the consternation of his mother, Lady Crackenthorpe. Fearing that Anthony will become infatuated with Peggy, the snobbish Lady Crackenthorpe persuades Jimmy Keppel to court the young woman, unaware that Anthony is already in love with Mrs. O'Mara. Oblivious to Jimmy's advances, Peggy spends her time writing plays. Upon learning that Anthony and her mother will not wed until she herself has married, Peggy leaves home on the pretense of eloping with Jimmy. She arrives in the city, where her purse is stolen. Penniless, Peggy spends the night in Jimmy's empty apartment. The next morning, Jimmy enters his flat and is amazed to find Peggy and is further surprised to read the announcement of their marriage in the newspaper. Soon after, Lady Crackenthorpe arrives furious; the news that the marriage never took place fails to assuage her anger, but Peggy saves the day by deciding that she really loves Jimmy and will marry him "all of a sudden."