Watch on Demand < Back Now Playing MASTERPIECE: MYSTERY! "Sherlock, Series 2: The Hounds of Baskerville" Airdate: 2012-08-09 Visit the Web site > Sherlock and Watson pursue the trail of the Baskerville experiments — top-secret government research on genetically engineered gigantic animals for military use. Or so it is rumored. Whatever the truth, something big is up on the moors.