Jealous of the attention his wife Virginia receives at a seaside resort and desiring to know how far her flirtation with Henry Harding has gone, George Conklin returns to New York to hire a detective. He finds a pretty girl in his house and the police identify her as criminal Philadelphia Mary but George tells them that she is his niece that he was expecting; when the police are gone, George learns that her name is Betty McCarthy and makes her agree to spy on Virginia. Betty becomes friendly with Virginia and falls in love with Virginia's ardent brother Billy Kent. Incensed at her husband's jealousy, Virginia plans to elope with Harding--who, Betty discovers, is only interested in Virginia's jewels. After the police arrest Harding when Betty tells them that he has the Conklins' jewels, Betty and Billy marry. Harding is released when Betty confesses she substituted candy for the jewels, the Conklins are reconciled, and Betty reveals that she really is George's niece.—AFI