Doug gets a sizeable bonus for Christmas and wants to put it in the bank to save for a rainy day. Carrie wants to invest the extra money in stocks for a new online company. Doug reluctantly agrees, but becomes obsessed with watching the stock market - go up and down. He panics when the stock goes down a point and insists they sell, only to see the stock double the next day. They buy the stock back, at double the original price, and this time promise to hold on to it and ride out the ups and downs.
Meanwhile, Arthur is feuding with the neighbors over who can have the biggest and best Christmas decorations.