Résumé
The narrative follows Arthur Burdon, a pragmatic surgeon, and his fiancée, Margaret Dauncey, an art student, whose lives in Parisian artistic circles are irrevocably altered by the enigmatic Oliver Haddo. Haddo, a flamboyant self-proclaimed magician and alchemist, challenges Arthur's scientific skepticism with his occult demonstrations and manipulative charm. Margaret, initially disturbed, falls under Haddo's hypnotic influence, leading her to abandon Arthur and undergo a disturbing personality transformation. She eventually reveals Haddo's supernatural hold, his use of her for revenge against Arthur, and his sinister 'magical operation' involving homunculi. Arthur attempts to rescue her, but Margaret, mentally tormented, repeatedly succumbs to Haddo's power. Driven by a premonition and later by Margaret's reported death, Arthur, aided by Dr. Porhoët, delves into the occult to uncover the truth. After a necromantic ritual confirms foul play, Arthur confronts and strangles Haddo. Though Haddo's body initially vanishes, Arthur, Susie, and Dr. Porhoët ultimately discover Haddo's attic laboratory filled with grotesque, partially formed homunculi and Haddo's strangled body. Arthur destroys the manor and Haddo's abominable creations, finding a measure of peace. The story explores themes of love, art, science versus the occult, psychological manipulation, and revenge, set against the backdrop of Paris and the English countryside.