The Dark Corner of the Old Building

Tenants in an old building in the city's historic district vanish without a trace. Their luggage and documents remain untouched, and the scene is unnervingly clean. Private detective Chen Mo takes the case, and the clues point straight to the mysterious female neighbor upstairs: strange noises in the hallway late at night, tenants who never open their doors or speak, and blind spots with no surveillance cameras. One disappearance leads to a secret buried deep within the old building. The truth is hidden in every echo that goes unanswered.