Watson visits Holmes at Christmastime and finds him contemplating a battered old hat, brought to him by the commissionaire Peterson after it and a Christmas goose had been dropped by a man in a scuffle with some street ruffians. Peterson takes the goose home to eat it, but comes back later with a precious carbuncle that his wife found in the bird's crop.
Holmes cannot resist a good mystery, and he and Watson set out across the city to determine exactly how the stolen jewel wound up in a goose's crop. In doing so, they unravel an intricate criminal plot and set free a man falsely accused of a crime.
"The Adventure of the Blue Carbuncle" is one of the 56 short Sherlock Holmes stories written by Sir Arthur Conan Doyle. It is the seventh of 12 stories in The Adventures of Sherlock Holmes, which was first published in Strand Magazine in January 1892.
