Book 4 After a short trip away from work, Sherlock and Sophia are back, and when an apparent 'gas leak' sets off an explosion opposite 221, the pair, along with their blogger John Watson, are hurtled into a game in which several hostages are in risk of blowing up if the two detectives don't solve the puzzle in time. Will they complete the cases in time, or will the bombs go off?
19 parts