The Lonely House

An orphaned heiress arrives at her distant relatives' isolated villa on the French Riviera, hoping for a fresh start after her aunt's death. Instead, Lily Fairfield finds La Solitude lived up to its name: a crumbling estate inhabited by a debt-ridden Count and Countess whose welcome curdles into something sinister almost immediately. When a body surfaces near the grounds, Lily's new home transforms from lonely to lethal, and she has nowhere to turn except to the enigmatic secret serviceman she met aboard ship, Hercules Popeau. Marie Belloc Lowndes, who also wrote The Lodger, weaves gothic atmosphere with early detective fiction in this 1920 thriller. The novel carries an irresistible historical footnote: Lowndes later claimed Agatha Christie borrowed heavily from her Popeau when creating Hercule Poirot, sparking one of detective fiction's most fascinating disputes over borrowed genius.