Another Open Road Katherine Kurtz Daily deal $1.99 in the US (Note NOT part of her Deryni series)
https://www.amazon.com/Lammas-Night-.../dp/B01FRQEV9W
https://store.kobobooks.com/en-us/ebook/lammas-night
An ingenious melding of espionage and the occult based in part on a true event in the secret history of the Battle of Britain during World War II.
The year is 1940, and Great Britain’s forces struggle against the invincible Nazi war machine. France has fallen easily to Adolf Hitler’s army and England is next in his sights. A British secret agent pays the ultimate price to deliver early warning of the Führer’s secret plan to harness the awesome power of the occult to conquer Great Britain by launching a supernatural assault that no defending military force could possibly deflect.
British Intelligence operative Col. John “Gray” Graham of MI6 is not only a valuable player in the great game of wartime espionage, he is also a practitioner of the ancient occult arts. In this life—and other lives before—Gray’s destiny has been firmly intertwined with that of his close friend Prince William of the British royal family.
Now, with the future of Britain at stake, these two men, the spy and the royal, must rally the hidden adherents of the Old Religion, hoping to unite the British covens in defense of their endangered island homeland. But it will take more than combined Wiccan sorcery to repel the Reich’s black magic on Lammas Night—and the sacrifice required might be greater than imagined and truly terrible to endure.