The Irish Witch: Dennis Wheatley

Roger Brook XI. As William Pitt the Younger's special agent, Roger Brook has faced untold dangers. But he is completely unprepared for the satanic practices of the Irish Witch, Abbess of the new Hell Fire Club and ringleader of the secret spy ring which passes information to the enemy. Then Roger learns that his young and beautiful daughter has been abducted in readiness for the sacrificial violation of a virgin at the Black Mass of Walpurgis Night...