Set in late January and early February of 1891, during the time that Professor Moriarty declares in The Final Problem, that Holmes had "incommoded" his plans, Holmes and Watson are visited by two charwomen and retained to clear the name of a drunkard lighthouse keeper who has been arrested and charged with the murder of a German man in Tynemouth, England. After learning the name of the unfortunate German man, Gustav Oberstein, Holmes realizes that the case has much greater significance than the simple murder of a German in the Tynemouth lighthouse. So begins a battle of wits between Holmes and Professor Moriarty. Holmes must determine the meaning of the German's last words and solve a mystery that will prevent the deaths of countless people in England and the Continent—a mystery that grabs the attention of the highest levels of the British government. Holmes's very life is on the line as he and Watson comb the English Northeast and the depths of London to solve the mystery of The Green Dragon and bring ruin to the Moriarty syndicate. The game is afoot!