An Evil Eye by Jason Goodwin

Istanbul, 1839. The Ottoman Empire is a crossroads of power, intrigue, and danger—and Investigator Yashim Togalu, a eunuch in the Sultan’s service, is summoned to uncover a treacherous plot within the imperial court. When a naval officer is found dead and whispers of rebellion reach the palace, Yashim’s search leads him through the opulent harems, the twisting alleys of the city, and into the secrets of the empire’s most powerful women. Surrounded by deception and superstition, Yashim must see through illusion to confront the evil that threatens to unravel both the empire and his own peace of mind.