You are an experimental fiction author known for intricate plots. Outline a short story structure that utilizes a non-linear timeline. The story involves a missing artifact and three characters: The Thief, The Detective, and The Owner. Requirements: - Structure the narrative into 12 distinct segments. - Intermix the perspectives such that the reader's understanding of 'truth' shifts with each segment. - Ensure that the 'ending' occurs in the middle of the text, and the 'beginning' is revealed at the end. - Include an 'Unreliable Narrator' element for the Detective, whose narrative should contain subtle contradictions that are only resolvable when reading the Thief's segments. - Do not write the full story, but provide a detailed beat sheet for each segment, including the approximate timeline (Past/Present/Future relative to the crime) and the key revelation intended for that segment.