With Buckingham Palace a smouldering ruin, Dr Mabuse and most of his Nazi cohort dead, and Mycroft in the hands of the O.S.S., Sherlock Holmes discovers the fight for Freedom still has a long way to go, and that Dr Watson, Mrs Hudson, the Baker Street Irregulars, and himself are in a fight that they may not all survive. Their only hope is the discovery of new allies to join them in the battle against new and sinister enemies bent on their destruction.