Barb Hambly - Those Who Hunt the Night

Used paperback.

At the turn of the twentieth century, a former spy is called into service to hunt down a vampire killer...

Once a spy for Queen Victoria, James Asher has fought for Britain on every continent, using his quick wits to protect the Empire at all costs. After years of grueling service, he marries and retires to a simple academic’s life at Oxford. But his peace is shattered one night with the arrival of a Spanish vampire named Don Simon. Don Simon can disappear into fog, move faster than the eye can see, and immobilize Asher—and his young bride—with a wave of his hand. Asher is at his mercy, and has no choice but to give his help.

Because someone is killing the vampires of London, and James Asher must find out who—before he becomes a victim himself.