In the opening chapter of “The Mysterious Affair at Styles,” the narrator, invalided from the Front and on sick leave, recounts his reconnection with John Cavendish, leading to an invitation to stay at Styles, John’s mother, Mrs. Cavendish’s estate in Essex. John reveals his mother has remarried a much younger man, Alfred Inglethorp, stirring family tensions and suspicion. The estate, Styles Court, holds significance as it was left to Mrs. Cavendish for her lifetime by her late husband, causing issues of inheritance for John and his brother Lawrence.

Upon arrival, the narrator describes the peaceful Essex country amidst the chaos of the Great War. He meets various members of the household: Mrs. Cavendish’s new husband Alfred, with a conspicuous black beard and patents leather boots; Evie Howard, a long-time family ally with a formidable presence; Mary Cavendish, John’s wife, who captures the narrator’s admiration with her striking features and profoundness; and Cynthia Murdoch, a spirited young woman working at a Red Cross Hospital, taken in by Mrs. Cavendish after her parents’ downfall.

The chapter sets a scene of underlying friction and complexity, notably through the disapproval surrounding Mrs. Cavendish’s recent marriage to Alfred, a man deemed unsuitable by her family. John and Lawrence, Mrs. Cavendish’s stepsons, along with Evie and the household staff, showcase a blend of duty, respect, and dissent towards the family matriarch and her new husband. Their country life, marked by contributions to the war effort and personal dilemmas, contrasts sharply with the looming crisis within.

The narrator’s interactions with the household members outline key personalities and dynamics, such as Mary Cavendish’s enigmatic allure, Cynthia’s vivacity, and Evie’s abrupt decision to leave Styles after a confrontation, stressing her fears for Mrs. Cavendish’s safety in Alfred’s company. Casual mentions of poison and detection, alongside introductions to characters like Dr. Bauerstein, a poison expert, and a veiled reference to Lawrence Cavendish’s troubled demeanor, lace the narrative with foreshadowing of deeper mysteries and conflicts.

Styles Court, embodying tranquility amidst turmoil and harboring its share of secrets and discord, serves as the nexus for unfolding events, setting the stage for a story intertwining family loyalty, hidden motives, and the unsettling element of murder.