As the much-anticipated date approaches for the double wedding of Elizabeth to John and Mary to Bill, the Classen sisters are trying their best to get everything just right. While Martha deals with the picky wedding-cake baker, who just can't seem to make up her mind, the sisters receive a flurry of incoming mail. To their delight, most of it consists of congratulations and RSVPs for the wedding ceremony. However, one letter in a bright red envelope...