On Christmas Eve, Sherlock Holmes and Dr. Watson try to determine how a fabulous blue carbuncle found its way down the gullet of a goose. It all starts that morning when the Commissioner who lives across the way asks Holmes' advice. On his way home, he came across a group of ruffians taking advantage of an elderly gentleman. His uniform scared them all off with the elderly gentleman leaving behind the goose. Holmes suggests that he simply keep it but he is soon back with the precious stone. Newspaper reports have reported the theft of the unique blue stone from a local hotel, but Holmes can't resist solving the mystery of how it got to its final destination.