When attractive Connie Ennis buys an expensive electric train set during the Christmas rush at Crowley's, a New York department store, without asking a single question about it, clerk Steve Mason becomes suspicious. Steve's suspicions are justified as Connie works as a professional "comparison shopper" for one of Crowley's competitors. Exhausted after a day of "shopping," Connie, a war widow, goes home to her six-year-old son Timmy and brings the electric train with her. The impressionable Timmy sneaks a peek at the train and gleefully assumes it is his Christmas present until Connie, who is unaware that he has seen it, informs him otherwise. That night, Connie's longtime admirer, lawyer Carl Davis, proposes to her, but unsure of her feelings, she declines to give him an immediate answer. Connie then discusses Carl's proposal with Timmy, who resists the idea. The next day, when Connie tries to return the train at Crowley's, Steve threatens to report her to the store detective. After she explains that she is a war widow with a son to support, however, Steve refunds her money, a gesture that leads to his dismissal. Steve then asks Connie to lunch and, while eating with her in Central Park, impresses her with his plans to build sailboats with his friend in Balboa, California. Later, as they are loaded down with comparison shopping packages, Connie and Steve become separated in a crowd. Steve, however, shows up later at Connie's apartment and discovers Carl there. Although polite, Carl is clearly disturbed by Steve's presence and fights with Timmy, who is still upset about the train. After a frustrated Carl leaves, Steve angers Connie by suggesting that she stop trying to make Timmy into the image of his dead father. Steve then learns about the train from Timmy and advises him to always "aim higher than the mark." As he is leaving, Steve impulsively gives Connie a passionate kiss, prompting her to accept Carl's proposal that night. On Christmas morning, Timmy discovers the train set outside the apartment door and assumes that it is from his mother. When he reveals that he earlier told Steve about seeing the train, Connie deduces where it came from and goes to confront Steve. Connie finds the almost broke Steve in Central Park, and although she offers to reimburse him for the train, he refuses her money, saying that he wants to encourage Timmy's optimism. After Connie gives him the loud tie she had bought for Carl, Steve happily offers his old tie to a passing bum. Connie then reveals she is marrying Carl on New Year's Day, sparking another lecture from Steve about letting go of the past and facing the future without fear. Annoyed by Steve's words, Connie leaves the park in a huff and goes home to Timmy, Carl and her former in-laws. Soon after, Connie is summoned to the police station to vouch for Steve, who was arrested after the police found him with a pair of stolen salt and pepper shakers, which the park bum had given to him as a gift. With Carl and Timmy by her side, Connie explains about Steve and the bum to a bemused police lieutenant, who eventually releases Steve. Timmy then insists that Steve eat Christmas dinner with them. At Connie's, the two rivals maintain a polite facade until Steve finally announces that he is in love with Connie and wants to marry her. Connie coolly tells Steve to leave, and Steve, who is planning to move to California as soon as he has earned enough money for a train ticket, says a final goodbye. The next day, however, Timmy takes his train set back to Crowley's and tearfully asks Mr. Crowley for a refund so that Steve will not be penniless. After Timmy returns home and presents a worried Connie with his refund money, she and Carl drive to Steve's hotel. When Connie refuses to see Steve, Carl deduces that she is genuinely in love with him and graciously "divorces" her. Connie then delivers the money to Steve, but he refuses to propose again until she has proven to him that she is through grieving for her husband. Once again, Connie storms off in anger, but later, on a lonely New Year's Eve, she realizes her future is with Steve. As Steve celebrates the New Year on a west-bound train, he receives a telegram informing him that Connie and Timmy are joining him and rushes happily to embrace them between cars.