Elliott and J. C. Nugent adapted their own play about a family led by an elderly man with three daughters. They call a plumber who ends up marrying the two unmarried sisters.
Dad Bence (J. C. Nugent) is a crotchety old man who has $100,000 but is concerned how his daughters are spending his money. Millionaire Duke Merrill (Roland Young) is in love with Kate Bence (Norma Lee) and secretly published her novel without telling her. After two years of letting her be creative, he asks her to marry him; but she refuses because she does not feel he values her. Duke goes off to get drunk with Ben Wade (James Donlan) who is married to the oldest Bence daughter Jane (Leora Spellman).
Young Kempy (Elliott Nugent) arrives at the Bence house to fix their plumbing and tells Kate that he makes $4 an hour and that her father left the house without telling him what needs fixing. Kempy says he read a book that told him he should act to get what he wants, and she informs him that she wrote that book. He tells her that he is determined to marry the author of that book, and she suggests they go off and get married right away. He agrees, and they leave the house.
The Bence family gets a telephone call from Kate who tells them that she just got married. They assume that she married Duke.
When Kate and Kempy return to the house, the Bence family is shocked that the couple got married after only knowing each other for a few hours. Dad wants to talk to Kempy privately but has difficulty seeing him alone. Kate goes up to her room, and Kempy talks much with Ruth Bence (Marion Spellman), and they immediately take a liking to each other. Dad orders Kempy to leave his house, and Kempy says he will stay in a hotel. Dad and Ma go into their room where he is miserable because the water is still off, and he needs some soda.
Kate and Kempy quarrel when she plans to move away to try out for a musical comedy. She makes a phone call and promises she will be there for the try-out.
Kate and Jane learn that Duke and Ben are drinking at a pub, and they go off to find them. As they go out, Duke comes in and talks with Ruth and Kempy. He is surprised to learn that Kate married Kempy who tells him he is an architect who designed a church after he got the idea from Kate’s book. Duke has just taken the option to buy the Bence home from Ben and Jane, and he offers to sell it to Kempy for his church design. Kempy agrees.
When Dad comes out of his room, Kempy says he owns the house now and can order him to leave, but he allows Dad to stay in his room.
Eventually Ruth produces Kempy’s wrench so that he can turn on the water, and he is surprised to find that she cleaned it for him. She tells him he can sleep on the couch which is the dog’s bed, and she brings in the dog from her room.
Finally Kempy gets the water turned back on so that Dad can get some water for the soda Ma has prepared. Kempy tells Duke that he is only twenty years old and too young to get married without his parents’ consent. Duke is a lawyer, and Kate realizes the marriage will be annulled. She learns she will not be in the musical comedy and agrees to marry Duke in the morning. Kempy follows Ruth outside and asks her to marry him the next day, and she agrees.