Marcellus Holloway, a rich widower, buries himself among his books and allows his only daughter, Penelope, to bring herself up. At the age of eighteen she was courageous and self-reliant, also self-willed and independent, with a disregard for the restraints of convention. She caused gossip by fishing on Sunday and galloping wildly about on her colt. An old friend, Mrs. Travers, and her son, Jimmy, visit them. Jimmy and Penelope become friendly. Mrs. Travers induces the father to allow Penelope to enter a fashionable boarding school with her daughter. Marjorie. At the school Penelope’s behavior is not as dignified as it should be. Her father dies and Penelope refuses to see her friends or return to school. Jimmy finally persuades her to come and make his mother a visit. She goes and at a party in her honor meets Mr. and Mrs. Rivers and enjoys Rivers’ company, causing his wife much anger. At the golf club she continues flirting and Jimmy remonstrates with her without success. Mrs. Rivers puts detectives on her husband’s trail and they follow Rivers and Penelope to a roadhouse. On the way Jimmy joins them. They arrive just as Rivers is beginning to show his real self to Penelope and she faints. The detectives take Rivers away, while Jimmy goes to Penelope. Mrs. Rivers starts a divorce suit, naming Penelope as a co-respondent. Penelope goes to Mrs. Rivers and pleads with her. Mrs. Rivers sees she is innocent and returns with her to the Travers’ home, where Jimmy takes her into his arms.