Agatha Christie's inaugural novel, "The Mysterious Affair at Styles," originated from a challenge issued by her sister, Madge, to craft a story. The narrative commences as Captain Hastings returns to England after World War I, invited to recover at Styles Court by his friend John Cavendish. During his stay, he encounters John's stepmother, Mrs. Inglethorp, and her new husband, Alfred. Despite the tranquil setting, Hastings gradually senses that something is amiss. When Mrs. Inglethorp is discovered poisoned, suspicion blankets the family, prompting the arrival of another old acquaintance, Hercule Poirot, to undertake an investigation.