Kingdom of Fire by Ana Calin

I followed the King of Flames to the darkest depths of the Underworld, into his Fire Realm. I am to become his queen, but can I go through with it, considering how I’ve had to betray him? But it turns out I’m not the only one who’s been keeping secrets, and his is even darker. We’re hurt, broken, and vicious with each other, and I don’t think we can still work things out, not after what we’ve done to each other. But doom is hovering over the world, and only the two of us, together, can fight it. We’ll save the world or go down with it, but it will take a miracle to save us.