The setting is London, in Victorian England. You start off at home in Baker Street at 8am one Monday morning. On leaving your house you must hail a cab, set off to find a crime and then solve it.
To move between the many instructions sections of the game you have to take cabs. You tell the cabbie where in London you want to go and then wait until you arrive at your destination. The problem with this is that you must know the places where Sherlock would go to - if you don't then the game comes to a standstill because you can't go very far on foot.
Just like its predecessor The Hobbit, you should enter instructions in full sentences. Some screens have a small picture although all have detailed descriptions.
The game is hard and will take months of playing to complete. Any buyers should bear in mind that reading Sherlock Holmes books might help.