The Vampire of Montana - Agents of the Royal States, #1

As a member of the RPS, Daphne Niell, also known as the Vampire of Montana, lives to serve. On a good day, she hunts terrorists and eliminates them before they can strike. On a bad one, His Royal Majesty of Montana, also known as her twerp of a cousin, sends her overseas to play nice with foreign monarchs. Upon landing in Spain, the Vampire of Montana learns she's been played, and her first job involves securing the life and liberty of everyone in a busy airport.
To do her job, she needs more than just an excuse: she needs a partner. Selecting a tall, dark, and handsome stranger from the ticketing line to become an unwitting accomplice in her plans isn't her style, but desperate times call for drastic measures. What she doesn't know might kill them both and forever change the course of the Royal States and the world.