Den of Blades and Briars (The Broken Kingdoms, #7)

Synopsis:

She’s bound to serve her enemy for a hundred years. Now, she’s at risk of killing the man … or falling for him.

After she lands on the losing side of a war, Saga is sentenced to serve Ari Sekundär, the man she despises.

But when a botched assassination attempt puts Saga on the run with her reluctant master, they’re forced to work together to survive. Soon hate feels more like passion and disgust more like desire.

What Ari doesn't know is that falling in love with the enemy will have deadly consequences. But how can Saga tell him, if he ever gives his heart to her, it will unlock a hidden secret that can destroy the kingdom…and end her life.