This is an enjoyable and effective blending of Sherlock Holmes and a sequel to The Prisoner of Zenda. Sherlock Holmes is consulted urgently by Colonel Sapt of the Ruritanian Royal Court, he needs Holmes' help in locating Rudolf Rassendyll, a double for the King of Ruritania. Rassendyll had previously taken the place of the king to foil a plot by his half-brother Michael and Michael's ally Rupert of Hentzau. Now Hentzau was active again and Rassendyll had disappeared. Holmes quickly realised that Rassendyll has been abducted by Rupert of Hentzau and that a very clever conspiracy in underway. The story sets of at a great pace and continues that way up to the end. The reveals are nicely paced and the climax is suitable and very satisfying.
The most significant problem this story has is to be true in spirit and sufficient detail to two very different sources, it manages this difficult task with skill. There two elements easily interweave and support each other. The classical Sherlock Holmes elements regarding deduction and planing are nicely counterpointed by the swashbuckling adventure the story requires, in particular at the climax the two elements are brilliantly combined.
David Stuart Davies has taken over the cast from both sources with tact and skill and manages to make them his own without undermining the originals. Watson is an effective narrator, Sherlock Holmes is as quick and resourceful as he should be, the Ruritanian cast are romantic and brave, the star is Rupert of Hentzau. He is a very effective villain, capable and ruthless, the correct mix of charm and savage will, he creates a genuine problem for Holmes to resolve and this lifts the book out of the risk of flaccid makeover. This is a great romp and a sincere tribute to the two glorious originals.