The blue carbuncle

Soon after Christmas, Peterson, a commissionaire, has become the happy owner of a good fat goose, in a unusual way. Even more peculiar is the special gift he finds in its crop: a wonderful big blue gem!

At first, Peterson, who knows Sherlock and is an honest man, comes to see the detective with the goose and an old scorn hat. Both have been lost by a poor man, who were fighting with others in a street. Seeing Peterson's uniform, everybody ran away... The commissionaire doesn't wish to keep the poor man's belonging, and hope that Sherlock will find him. There is a name, Henry Baker, but it's a very common one.

To Sherlock's eyes, however, there is much more to learn from both item. 

To Watson, who declare not to see any clue, he answers:

"On the contrary, Watson, you can see everything. You fail, however, to reason from what you see. You are too timid in drawing your inferences."

The goose will not keep for long, so Sherlock gives it back to Peterson to be cooked. But when his wife wants to do it, she finds the beautiful gem, no doubt the very one that has been stolen a few days ago. But how did it arrive there?

It's rare enough to be noticed: this adventure is a funny one, completely fantastic, full of peripeteii, unexpected turns, mistakes and misunderstandings... From the bedroom of a Countess at the Hotel Cosmopolitan to the crop of a goose, the blue carbuncle will make a extraordinary journey, and us with it.
Beside, it ends with Sherlock showing his better side: magnanimity and some nobility of soul.
On the whole, an excellent adventure!