The best book Dickson has turned out -- complete baffler with a good share of humor. Sir Henry Merivale and two of his agents are in a plane which arrives, by accident, but none the less expected, at an old Chateau. Mystery -- who and where is Casquet, the chief of the French SurotÉ; who and where is the notorious thief and murderer. There's a light-hearted flair which is refreshing.