Eternity and One Day - Doran Simmons

She negotiated seventeen treaties. She never expected to become one.

When the Ashveil-Solaris Accord demands a political marriage to end a thousand-year war, sun-elf diplomat Caelindra Voss signs on the dotted line with the composed fury of a woman who helped draft the contract without knowing she was in it. The groom: Dorian Ashveil, vampire lord, one thousand and twelve years old, and visibly as thrilled about the arrangement as she is.

Neither of them is going to perform enthusiasm they do not feel. What they are going to do, in the rambling, inconsistent, deeply peculiar castle on the border between their two courts, is survive eternity with their dignity intact.

The problem is that dignity, it turns out, is considerably more entertaining when the other person is also trying to keep theirs.

What begins with an enchanted staircase that becomes a slide and formal robes that sing bawdy tavern songs at the worst possible moments evolves into something neither of them was prepared for: a prank war of escalating craft and genuine joy, a shared library at midnight, a corridor of shadow-craft that says what hasn't been said, and the slow, certain discovery that two people who have been alive for centuries can still be surprised.

Meanwhile, their scheming courts are watching. A faction wants the Accord dead. The permanent record is about to contain the truth.

Eternity and One Day is the story of two immortals who were given forever and decided to be interesting with it. It is about the specific pleasure of being genuinely known. It is about what peace actually looks like when it stops being a treaty and starts being a life.

The war lasted a thousand years. The rest is going to take considerably longer.

And neither of them minds at all.