Beautiful young Charisa Templeton always loved her father's old friend the Marquis of Mawdelyn – and as a child she roamed Mawdelyn Priory with his nephew Vincent, whom she adored. Saddened to hear that the Marquis has died – she's glad his heir, Vincent, will be coming home from his army posting in India to claim his title. But then Fate strikes another blow with the news that Vincent has been killed! Reluctantly, Charisa and her father prepare to welcome the next in line – half-French Gervais Mawde. But as soon as he arrives they sense something is wrong. Penniless, he immediately sets about selling off the family treasures and dismissing loyal servants, even the Vicar! Worse still he forces his attentions on a shy and unworldly Charisa. But just as she begins to despair, her prayers are answered and Vincent appears – alive, but in terrible danger. Someone is trying to kill him and now they realise who! None other than Gervais who is not only a murderer but also a Devil worshipper, planning to use innocent Charisa in his satanic Black Mass. The question is, can Love conquer the forces of darkness?