When serviceman and author Jim Scott returns from Paris to New York City, his hometown, he is flabbergasted to discover that his well-meaning but unrealistic wife Connie has invested his wages in a run-down apartment building. Connie has been transforming the basement into an apartment for herself and Jim, and furnishing the rest of the building with inherited antiques. Despite Connie's hopes that being a landlord will give Jim time to write a novel, Jim realizes that the building will require much work and will barely give them enough income. Nonetheless, Jim is happy to see his lovely wife, although their reunion is interrupted by the arrival of smooth-talking Charley Patterson, an older man searching for a room. Unknown to the Scotts, Patterson is a confidence man who romances and swindles wealthy widows. After the Scotts rent a room to Patterson, Jim decides that he will save money by fixing a leaky sink himself, but his efforts make the problem worse, and a plumber is called in. Several more costly repairs convince Jim to delay writing his novel and prepare a few magazine stories to make some quick money. Meanwhile, Charley meets his neighboor in the building, gentle widow Eadie Gaynor and her daughter Florence, and becomes enamoured of Eadie even though she is poor. Later, Connie becomes suspicious of Charley when a potential tenant thinks that she recognizes him as a man who swindled her years earlier. After the woman leaves, however, a pleased Jim persuades Connie to rent the vacant apartment to his old Army buddy Bobbie. When Bobbie arrives, Connie is shocked to see that she is a stunning former WAC named Roberta Stevens. Jim tries to alleviate Connie's jealousy by offering to take her out for their wedding anniversary the next day. Soon after, FBI agent Gray arrives and questions them about Charley, although he refuses to explain his interest in him. The next night, Connie and Jim go to a nightclub, and there see Charley dining with a woman they do not recognize, even though he had told Eadie that he would be on business in Baltimore. Later, an inspector from the Department of Housing and Building informs the Scotts that the exposed wiring in their building is a serious code violation, and that if it is not fixed within fifteen days, the building will be condemned. That night, Charley and Eadie announce their engagement, worrying Connie. Charley and Eadie leave the next day to be married, after which Jim learns that it will be so expensive to fix the wiring that he must sell the building. Jim and Connie have received no offers by the time Charley and Eadie return, and Charley lends Jim the $800 needed for the repairs. Jim still wants to sell, however, as he is convinced that the building will drive them deeper into debt. Connie and Jim argue about the building and Bobbie, of whom Connie is still jealous, and Jim storms out of their apartment to sleep in a hammock in the back yard. Jim ends up sleeping in Bobbie's empty apartment, as he knows that she is away on a modeling assignment, but the next morning, Bobbie returns home, and Connie mistakenly assumes that she and Jim have spent the night together. Connie's anger is deflected by a newspaper story concerning Mrs. Frazier, the woman she saw in the nightclub with Charley, who has been cheated by an "elderly Casanova" named Charley Price. The article details Price's career, stating that he has bilked numerous women in several states. Jim and Connie confront Charley, who admits that the charges are true. Charley assures them that he truly loves Eadie and has now retired, and defends himself by pointing out that he gave the widows romance in return for their money. When Jim warns him about the FBI, Charley decides to leave and send for Eadie later, but the police arrive before he can escape. As he is being taken away, Charley reassures Eadie that she is the only woman he has ever loved. Charley, who insists on paying for his crimes by pleading guilty, arranges for Jim to get arrested for receiving the $800 from him, as it was part of the money he took from Mrs. Frazier. Jim is infuriated when he is thrown in a cell with Charley, but the older man explains that he needed time to tell Jim his life story so that he can write a book about him. Jim is released the next day and writes Charley's book, which becomes a best-seller. After eighteen months, Charley is released from prison and reunites with Eadie. Later, Jim and Connie, who have beautified the apartment building with Jim's royalties, watch with amusement as Eadie and Charley take their newly born twin daughters for a walk.