Mary Thornton Brown, a wealthy heiress, decides to spend the summer working as a hired girl at a boarding house. She is seeking a change from her privileged life and hopes to gain a new perspective on the world. Over the course of her adventure, she meets Mrs. Roberts, the kind and wise boarding house owner; Sally, a hardworking and ambitious maid; and Harry, a charming and intelligent boarder. Mary learns about the challenges and rewards of working-class life, and she begins to question her own values. She also discovers that she has a talent for writing, and she begins to write a novel about her experiences. When her secret is finally revealed, she must confront the consequences of her deception.