The Desolate Reign by Amory Cannon

Emilia Aurelius should be a queen, but she’d settle for not being a fugitive. Taking refuge in the Borealis court seems her only chance to find a haven from Emperor Cyrus, who is playing a dangerous game of power with a set of rules all his own. Unfortunately her own country is on the brink of civil war, attacked from within and without by the very people she’s sworn to save—the Insurgos. With the truth of the Insurgos’ God and agenda murkier than ever, Emilia embarks on a treacherous quest for truth and her rightful place as queen. Neither will come without a price. Political pressure may force her to choose between her crown and her heart, while the search for ancient secrets unearths more questions than answers. A mysterious prisoner may hold the information she seeks if she’s willing to bargain. What is the Narrow Gate? Can she finish what she started and save the Insurgos from extinction… even if they don’t want to be saved?