Erma Desmond lives with her uncle and aunt on their large estate on Long Island. She is in love with Chester Clynch, but her uncle frowns upon her choice and the two decide to elope. Meanwhile, Mrs. Hugo Stanley, wife of a scientist and a lady of very uncertain temper, is holding the fort against her husband and daughter. She is in one of her moods, and the family fights shy of her. Erma plans to elope, but balks at the last moment and decides not to go. Her uncle, however, learns of her plans, and in his anger insists that she carry them out. She goes to the city and takes up her abode with a friend. Later, she leaves to accept a position as companion to Mrs. Stanley. The latter notes the marked likeness between the girl and herself and hires her. Mrs. Stanley then, her husband and daughter having gone off, leaves for a pleasure trip, installing Erma as head of the house and leaving her a check of large proportions to cover the expenses. There is a house party in progress at Stanley's at the time, but even the guests and servants fail to recognize Erma as the former employee, thinking that she has gone off. The only change they do note is in the remarkably sweet disposition of their mistress. Some time later, Stanley and the suitor for his daughter's hand, to whom Mrs. Stanley objected, return. Then the daughter comes home from boarding school, all of which greatly complicates matters and creates some highly dramatic and laughable situations. Stanley falls in love with his "wife" (who isn't his wife at all) and Gilberta, the daughter, smothers her "dear mother" with kisses. It's a lovely fix. Matters finally are straightened out, but not without many absorbing complications. Finally a message from the real Mrs. Stanley, who had fled to Reno, announcing that she has secured a divorce, clears the road for Stanley and Erma who wish nothing more.
—Moving Picture World synopsis