London 2023. During the inventory in Scotland Yard archives, an unclaimed parcel dated 1914 was discovered. Upon unwrapping, an object resembling a camera was revealed. However, the camera contained enigmatic symbols and locks instead of the common mechanism. The following note was enclosed:

"Dear Detectives,
Over all these years I have been investigating the most mysterious cases. Now it is time for me to retire, so I decided to entrust my life's work to one of you, to the most talented and capable detective. I am leaving you this creation of my own -- a camera with an encrypted mechanism. Open the camera and discover the identity of my successor!
Sincerely yours,
S. H."

Handwriting examination and other solid evidence helped to determine that the parcel was sent by none other than Sherlock Holmes! No one at Scotland Yard has succeeded in solving the detective's last mystery. Now we are passing the enigmatic camera on to you. We are convinced you will be able to solve the puzzle and reveal the identity of Sherlock Holmes' successor.