Pariah

In the city of Queen Mab, nothing is quite as it seems. Pariah, spy and Inquisitorial agent, Alizebeth Bequin is all of these things and yet none of them. An enigma, even to herself, she is caught between Inquisitors Gregor Eisenhorn and Gideon Ravenor, former allies now enemies who are playing a shadow game against a mysterious and deadly foe. Coveted by the Archenemy, pursued by the Inquisition, Bequin becomes embroiled in a dark plot of which she knows not her role or purpose. Helped by a disparate group of allies, she must unravel the secrets of her life and past if she is to survive a coming battle in which the line between friends and foes is fatally blurred.

Read it because
It's an intriguing and evocative story that shows characters you know and love through new (yet strangely familiar) eyes, and forges a stunning mystery that will leave you astonished.