The Curse of the Singing Wolf

Book 5 in a series of chronological stand-alone plots:France 1899. Dr Watson and Countess Volodymyrovna are holidaying in Biarritz when a fire breaks out in the kitchen of their petit hotel. The hotel's owner (a retired opera singer known as the Singing Wolf) invites the handful of guests to stay at her isolated mountain retreat in a remote area rife with wolves and lawless brigands led by the murderous outlaw, Sarazan.
Among the guests are Colonel James Isambard Moriarty, Baron Frederik Reichenbach, Herr Gustav von Gunn and Prince Anton Orczy. The four names send a shiver up the spines of our two sleuths but after arriving at the ancient Cathar fortress it is too late to turn back. During the night their hostess mysteriously vanishes. Suspicion falls on the brigands, the old servants, and then the gang of four when it becomes apparent that the original hotel fire was deliberately engineered to lure them all to Chanteloup.
The mystery of the disappearance of their hostess deepens. Is she dead or alive? Is there a lunatic at large? Is one of the men a murderer? Could all four be involved?Various motives present themselves: military conspiracy, religious martyrdom, sexual jealousy and hidden Cathar loot. Complicating the case is Countess V's growing attraction to the Irishman and his ardent pursuit of her affections.