Warning: Wikipedia contains spoilers
The story begins with Donald's nephews passing through Shacktown, the most impoverished area of Duckburg. They progressively get more depressed as they see the living conditions there, children of their age dressed in rags and having tired expressions, hunger and sickness evident in many of them. They feel responsible for it and want to help those poor children find some happiness. The Ducks have the idea of organizing a Christmas celebration.
They ask for the help of their Aunt Daisy Duck, president of a local ladies' society, and their friends in the Junior Woodchucks. But as it soon becomes evident that raising enough money is harder than it sounds. With all their efforts, they are still a hundred dollars short. Donald has the idea to ask his Uncle Scrooge for the money. Scrooge refuses his nephew's request for a donation, but nevertheless offers to match Donald's own fifty dollars, if he can manage to raise that much. Donald soon learns that asking for charity during the holidays, when every family struggles with its own increased expenses, is not a successful way to raise money. He tries to trick his Uncle into making the donation, but that fails too. Only when he swallows his pride and asks for his cousin Gladstone Gander's help does he finally succeed in raising his fifty dollars. When he arrives at his uncle's money bin, an apparently shocked Scrooge tells him it is too late. Enraged, Donald opens the vault door and discovers that inside, the overloaded floor had collapsed, and the money has been lost in the caverns below Duckburg. Now Donald still is fifty dollars short and has to take care of a shocked and depressed uncle.
Finally his nephews find a way to reach Scrooge's money and Scrooge promises them the first money to reach the surface. Which happens to be thousands of dollars. The story ends with a great Christmas celebration for the children of Shacktown.Plot