Where Empires Fall for You. The Hollow Crown Series, #4

She was trained to map the conspiracy, not fall for the crown prince at the center of it. Threadwitch operative Seraphina Voss has spent fourteen months embedded in the Vaelthorn court with one objective: identify the conspiracy unraveling the empire from within. She was never supposed to care who survived it. Now the conspiracy is moving faster than anyone predicted, the man she was sent to investigate has given her his full trust and his full authorization, and Seraphina is out of time - and out of exits.
To finish this, she'll have to open the Threadwork wider than it's ever been opened, face the truth about who is really pulling the strings - and decide, once and for all, whether she's willing to stay. Some stories end with a throne. This one ends with a choice.