A couple on the verge of divorce learns the wife is pregnant.

When Casanova "Cas" Q. Brown is greeted at the Rossmore, Illinois train station by Madge Ferris, he begs her never to let him out of her sight and never to mention New York. Several months later, Cas asks Madge's cantankerous father, J. J. Ferris, for permission to marry his daughter. Incredulous that anyone could love Madge, J. J. assumes that Cas is marrying her for her money and refuses permission on the grounds that he wants to spare Cas the fate that he has suffered. Cas and Madge decide to marry over her father's objections, and on the day of the wedding rehearsal, Cas receives a letter from a maternity hospital in Chicago, asking him to contact Dr. Martha Zernerke. Hastily excusing himself from the rehearsal, Cas confides to J. J. about his misadventure in New York: In a whirlwind romance, Cas meets and marries Isabel Drury. When Isabel brings her new husband home to meet her parents, her eccentric mother insists on consulting the stars about their matrimonial future. After Mrs. Drury proclaims that the position of the stars portends disaster, Cas offends his mother-in-law by opining that astrology is nonsensical. The relationship between Cas and his in-laws takes a turn for the worse when he burns down the Drury mansion with a discarded cigarette that he was trying to hide from Mrs. Drury. When Mrs. Drury declares the fire to be an astral warning, Cas, exasperated, storms off, leaving behind a sobbing Isabel and an annuled marriage. Upon concluding his story, Cas tells J. J. that he has decided to go to Chicago to investigate the letter, but plans to return that night in time to marry Madge. At the hospital, Cas meets Dr. Zernerke, who, after showing him his baby daughter, informs him that Isabel has decided to put the infant up for adoption. When Cas confronts Isabel about the adoption, he admits that he still loves her, but she reproaches him for not writing and reminds him of his impending marriage. To prevent losing his daughter, Cas poses as a doctor and kidnaps the baby. As Cas exits the hospital with his daughter, Isabel tells Dr. Zernerke that the adoption was just a ruse to test Cas's intentions and that she now wants to reconcile with him. Meanwhile, back in Rossmore, Madge, dressed in her bridal finery, is awaiting her groom when Cas calls J. J. to inform him about the baby. Calmly turning to his wife and daughter, J. J. announces that Cas cannot make the wedding and suggests going to a movie instead. Cas takes the baby to his hotel room where, aided by Monica, the maid, and Frank, the bell captain, he strives to perfect a baby formula. Cas's daily bulletins about the baby's health do nothing to mollify Isabel, however. When Frank, wearing his hotel uniform, visits the hospital in search of the perfect formula, Cas fears that the staff will trace the baby to the hotel and decides that he must marry immediately if he hopes to retain custody of his child. After he proposes to Monica, the female in closest proximity, the two rush to the marriage bureau. Meanwhile, Madge and her father and Isabel and her father arrive at Cas's hotel room, and Frank informs them that Cas has gone to City Hall to be married. Upon his return, Cas, alerted by Frank about his visitors, hides with the baby in a different room. While sobbing over her loss of Cas in the hotel hallway, Isabel hears her baby cry. Following the sound of the cries to Cas's room, Isabel enters to find Cas feeding their daughter. When Isabel admits that the adoption was a ruse to win Cas back, he tells her that he was prevented from marrying Monica by the state's requirement of a three-day waiting period. After the baby burps, Cas and Isabel reconcile, and Cas promises to teach her how to take care of their baby.