A straitlaced turn-of-the-century father presides over a family of boys and the mother who really rules the roost.

In New York City in 1883, businessman Clarence Day strives to run his Madison Avenue home as efficiently as his business. His temperamental outbursts over the smallest infractions so terrorize the servants that even the charm of his sweet-tempered wife Vinnie cannot keep a maid longer than a few days. Vinnie and Clare have four sons, all of whom are redheaded like their parents. The eldest, Clarence, Jr., is headed for Yale. John, the next eldest, likes to invent things, while brother Whitney struggles to learn his catechism, and Harlan, the youngest, is most interested in his dog. Knowing how much Clare dislikes it when visitors stay in the house, Vinnie neglects to tell her husband that their cousin, Cora Cartwright, and her young companion, Mary Skinner, will spend a week with them. Clare is even more put out when he learns that Vinnie has promised that he will take Cora and Mary to Delmonico's restaurant for dinner. As usual, however, Vinnie gets her way. Clare even agrees to take Clarence, who has developed a crush on Mary, to dinner. Later, Mary divulges that she is a Methodist, unlike the Days, who are Episcopalian. During the course of the ensuing religious discussion, it is revealed that Clare has never been baptized. Vinnie is very upset and insists that Clare rectify the oversight to ensure that they will be reunited after death, but Clare refuses, certain that God would never be so imprudent as to deny him entry into heaven. In the meantime, Clarence becomes convinced that wearing Clare's made-over suit forces him to behave like his father. When his stern reaction to Mary's innocent flirtation sends her away in tears, Clarence becomes determined to earn enough money to buy his own suit. He and John get a job selling patent medicine and try it on Vinnie without her knowledge. The medicine makes Vinnie so ill that Clare, believing her to be near death, promises that he will be baptized if she gets well. When Vinnie recovers, however, Clare reneges on his promise. Unknown to Clare, Vinnie then arranges for him to be baptized at a church in Audubon Park so that he will not be embarrassed in front of his acquaintances, but he remains adamantly opposed. Vinnie's opportunity arrives when Clare is repulsed by a ceramic pug dog that she recently purchased and refuses to be baptized as long as it remains in the house. Vinnie quickly dispatches Clarence to return the dog to the store and authorizes him to spend the money on a new suit, which just happens to cost exactly the same amount as the piece of pottery. The next morning, Cora and Mary return for another visit and, wearing his own suit, Clarence makes up with Mary. Taking advantage of the confusion, Vinnie arranges for an expensive cab to drive Clare to Audubon Park. Although Clare protests the expense and denies that he agreed to be baptized if the pug was returned, Vinnie uses her own subtle persuasion to round up the entire family to witness Clare's long-postponed baptism.