Pretty Irish lass Pegeen O'Barry lives in a small fishing village on the cost with her kind but alcoholic father and her vicious stepmother Moll. When her father is killed during a drunken brawl, a stunned Pegeen wanders down to the shore in her grief. She is noticed by Sir Arthur Ormsby, an Englishman who just happens to be sailing his yacht up the coast. He takes a liking to her and before long she's moved into his estate. Things are going along swimmingly until Arthur's wastrel brother Guy shows up.

Ellen Shannon, the daughter of self-made Irish politician Pat Shannon, is engaged to Ted Breslin, but because Pat began his career as a menial laborer, Ted's mother, Mrs. J. De Barth Breslin, refuses to sanction the marriage. Heartbroken, Ted takes up drinking and gambling with "Poker" LeMoyne and Don Jackson, while Ellen attends a finishing school hoping to improve herself. While trying to elude her chaperone, Ellen unwittingly dashes into a man's hotel room, and from the window, she witnesses Don and "Poker" playing cards, while Ted lies unconscious from too much drink. When the two gamblers quarrel, Don kills "Poker," but Ted is accused of the crime.

Ollie is a love-struck private who is drilled by his unsympathetic lieutenant at reveille. The colonel of the regiment wants his daughter to marry the lieutenant but she has her heart set on the chubby-faced Hardy, who himself is in love with another woman. He is thrown into a cell for disobeying orders, where he later escapes with the assistance of his sweetheart, and a casual touch of assault when he bumps the guard with his large stomach. The final chase scene ends with everyone getting what they want.

Plump and Runt are starving artists who are both in love with their pretty model. Runt chooses money over love and marries a widow he thinks is rich. It turns out the model is the real heiress, and Plump marries her.