The official trailer of the 221B Sherlock Holmes Alternate Reality Game. Play 221B here: http://www.221b.sh. The game itself is a two-player vehicle immersing you into the world of Sherlock Holmes and Dr. John Watson.

221B takes you through the events leading up to the very first scene of the new Sherlock Holmes film (which is due out in December). You can either play with a friend (ie: one as Holmes, one as Watson), or you can even play alone, taking on the role of both characters. You will be called on to investigate crimes, sift through evidence and solve mysteries. You'll also have to stake your reputation as detectives on your deductions.

You will need a Facebook account in order to play the game. There is a registration process which uses the Facebook Connect system to link you with a friend so that you can start playing.

Do you have what it takes? Go to http://www.221b.sh and start playing now.