The Black Tortoise: Being the Strange Story of Old Frick's Diamond

A private detective and his friend become involved when a wealthy old man's diamond vanishes amid visitors at his villa, including an intriguing English newcomer. The investigation moves through questioning, a surprising arrest, and a dramatic trial in which a photograph's trustworthiness becomes pivotal. Meanwhile the niece and another woman pursue their own inquiries, exposing conflicting motives and hidden relationships. The narrative alternates between procedural detail and personal observation, resolving tensions aboard a yacht and probing how identity, loyalty, and the limits of visible evidence shape the search for truth.