Sherlock Holmes: Consulting Detective Vol. I is an adventure game for the Sega Mega-CD based on the Sherlock Holmes series of books. In North America, the game was bundled with launch Sega CD units along with Sega Classics Arcade Collection (in the same box) and Sol-Feace.
The game was followed by Sherlock Holmes: Consulting Detective Vol. II, although in North America was curiously never released as a stand-alone product. Theoretically this means Vol. II is a great deal easier to find than Vol. I.