The Midnight Queen is set in London, in the year of the plague 1665. Sir Norman Kingsley visits the soothsayer "La Masque" who shows him the vision of a beautiful young lady. Falling madly in love with her, he is astonished to find her only a short time later and saves her from being buried alive. He takes her home to care for her, but while he fetches a doctor, she disappears. Sir Kingsley and his friend Ormistan embark on an adventure to solve the mystery of the young lady - will they ever find her again.