Based on a very successful play by J. Hartley Manners, an Irish lass inherits two million pounds but must spend three years in England and never see her father again, neither of which proves worth it.
In Ireland Pat O'Connell (J. Farrell MacDonald) provides a steady diet of fish for his daughter Peg (Marion Davies) until solicitor Gerald Markham (Onslow Stevens) informs him his father-in-law died and left two million pounds to Peg if she will live with Mrs. Chichester for three years and never see her father again. After a ship's crew is lost, Pat agrees. Peg says good-bye to her father, who calls her "Peg o' my heart."
At the large English house Peg finds the servants and inhabitants unfriendly. She sees Chris (Alan Mowbray) kiss Ethel (Juliette Compton), who sends her to the kitchen. Mrs. Chichester (Irene Browne) reminds her daughter Ethel they are penniless and are getting 5,000 pounds a year to board Peg, whom she calls Margaret. Peg refuses to give up her dog; but Gerald persuades them to let him stay in the stable, though Peg sneaks the dog into her bed. Peg tells Mrs. Chichester that she is not like a mother. Mrs. Chichester tells Ethel to marry Gerald and Alaric (Tyrell Davis) to marry Margaret. Gerald asks Ethel to marry, and she says yes.
Meanwhile Peg is falling in love with Gerald; but he promised not to say whom he loves. Alaric says love makes him silly. When he asks Peg to marry him, he is so inept that she laughs. When he says she must give up her dog, she refuses. Chris tells Ethel he can't get a divorce but wants to go on; but she says good-bye. Peg sings after a hunt, and Gerald proposes a toast to his future wife, Ethel, causing Peg to cry. Peg plans to visit her father. Pat meets Gerald in the garden and asks to see Peg unseen. Pat tells Gerald he is going to America and asks Gerald to say he is dead. Chris dances romantically with Peg, and Peg tells Gerald she wants to travel with her father. Gerald tells her he went to sea and is not coming back. Peg stops Ethel from going away with Chris and goes in a car to tell Chris not to do it. Peg tells Ethel Chris goes after many women. Chris's wife comes in with a lawyer, witnessing Peg coming forth in a robe, so that she can get a divorce, which is a revelation to the hidden Ethel. Gerald asks Peg about the rumor, and she learns these people are getting 5,000 pounds a year for mistreating her. Gerald tells Peg that her father is alive. Peg says money can't buy happiness and is angry at Gerald for lying. In Ireland Peg celebrates her birthday with her father, who takes her outside to get her wish, Gerald. Gerald tells Peg he loves her, and they kiss.
This story contrasts snobs who would be wealthy with the happiness of working people like Pat and Gerald as well as the irrepressible Peg, who loyally rejects such a hateful will and finds happiness anyway.