Plot
In 1928, aging and lonely Tarrytown, New York, millionaire Samuel Fulton decides to leave his fortune to the family of the late Millicent Blaisdell, the only woman he has ever been in love with, but did not love him back. Samuel explains to his lawyer Edward Norton that losing Millicent motivated him to become a wealthy businessman. When Norton fears the family will spend the money unwisely, Samuel decides to visit them in the small town of Hilverton, Vermont, renting a room in their house under the alias John Smith.
Although the family is initially reluctant to take in Samuel, the youngest daughter, Roberta, quickly makes him feel welcome. He notices that the Blaisdells are a happy family who, although poor, are proud of their background. Father Charles has taught the family not to prioritize material possessions, while mother Harriet wishes for her daughter Millicent "Millie" to marry Carl Pennock, a wealthy, snobbish young man who can buy Millie everything that Harriet never had. Millie, however, is not interested in Carl and prefers to marry Dan Stebbins, who works as a soda jerk in Charles' drugstore.
One night, Millie and Dan announce their engagement, which upsets Harriet. Shortly afterward, Norton arrives, announcing that the family has inherited $100,000 from an anonymous benefactor. The family immediately gives up their humble life for the upper-class lifestyle. After Harriet declares that Dan will not be able to financially support Millie, Dan breaks off their engagement, and Millie is forced to date Carl again. As the family moves into a lavish mansion, Harriet tells Samuel that he must move out, and Charles begrudgingly sells his store.
When Carl takes Millie to a speakeasy one night, Samuel helps them escape from a raid and is arrested in the process. Dan bails Samuel out. After learning that the oldest son, Howard, is faced with a $2,000 gambling debt, Samuel wins back Howard's IOU in a casino, but is captured in another raid. Dan bails Samuel out again and announces his decision to leave Hilverton to build a career. Seeking to bring Millie and Dan back together, Samuel sets up a meeting at the movies, but Dan rebuffs Millie and leaves. As Millie tearfully expresses her hatred for the family's sudden wealth, the Pennocks see Samuel comforting Millie and assume they are dating.
During a cocktail party at the Blaisdell house, Harriet overhears gossip about Samuel and Millie from the movie theater, and forces Millie to announce her engagement to Carl. At the engagement party, Charles reveals he has lost his investments, which makes Samuel realize that the Blaisdells are in no position to make wise financial decisions. At the behest of Samuel, Norton refuses to give them a loan, after which Charles begs the Pennocks for money. Upon learning that the Blaisdells are broke, the Pennocks refuse the loan and leave, calling off Millie and Carl's engagement.
Much to Harriet's distress, the Blaisdell family returns to their old lifestyle, Millie and Dan become engaged again, and Charles buys his store back. Roberta reveals that "John" has won the first prize at an art show, since she secretly entered his paintings. Samuel leaves the house to avoid the press after saying goodbye to the Blaisdells, who now think of him as the grandfather he could have been.
