Historical drama meets traditional murder mystery in this uneven but passionate debut. Istanbul in 1886 is in a state of enormous political and social unrest. Upper-class society has evolved a strange new stratum combining British expatriates, colonials and the clashing traditional and modern Turks, all struggling to find their place as the Ottoman Empire wanes. The citizens of Istanbul are leery of the bold and immodest behavior of the Englishwomen in their midst, but all are shocked when young Mary Dixon, governess at the imperial harem, is discovered brutally murdered. Few seem to have known the quiet, retiring Mary, but readers snatch a glimpse in the interwoven story of Jaanan, a young Turkish woman about to be forced into marriage to a man she hates and who has a strange connection to the murdered woman. The writing is lyrical and the characters enchanting, particularly Kamil Pasha, the region's magistrate, who finds himself entangled in the case. But the rich historical setting makes an uneasy match with the whodunit sleuthing; neither ends up being able to sustain the book, particularly given the placid pace of the investigation. (Feb.)