Valentine's Exile (Vampire Earth, #5)

David Valentine is revered as a hero for his part in fighting to regain Earth's freedom. When a former Quisling traitor is badly wounded, he asks Valentine to find his wife, who has vanished into the darkness of the Kurian Order. With the help of old friends and new allies, Valentine traces her to a mysterious, heavily guarded compound in Ohio. And what Valentine finds within will shake his sanity to its very core.