The Dragons of Deepwood Fen by Bradley P. Beaulieu

This 1st book in a new fantasy series from the author of the acclaimed Song of the Shattered Sands series follows an unlikely pair as they expose the secrets at the heart of the mountain city of Ancris.
Lorelei Aurelius is the smartest inquisitor in the mountain city of Ancris. When a mysterious tip leads her to a clandestine meeting between the Church and the hated Red Knives, she uncovers a plot that threatens not only her home but the empire itself.
The trail leads her to Rylan Holbrooke, a notorious thief posing as a dragon singer. Rylan came to Ancris to solve the very same mystery she stumbled onto. Knowing his incarceration could lead to the Red Knives' achieving their goals, Lorelei makes a fateful decision: she frees him.
Now branded as traitors, the two flee the city on dragonback. In the massive forest known as the Holt, they discover something terrible. The Red Knives are planning to awaken a powerful demigod in the holiest shrine in Ancris, and for some reason the Church is willing to allow it. It forces their return to Ancris, where the unlikely allies must rally the very people who've vowed to capture them before it's too late.
Explore the mountain city of Ancris, where fast-paced adventure and intrigue abound. in this new offering from the author of the acclaimed Song of the Shattered Sands series.