Continuous rain locked the entire small town, and the humid air was filled with lingering dullness. Lin Wan, who lived alone in an old building in an old alley, found an unsigned envelope stuffed under the crack of the door one night when thunder was roaring. The brown paper was wrinkled by the rain, but the handwriting was unusually neat, as if it were written stroke by stroke with the tip of a very fine pen. There was no greeting in the letter, only a fragmentary description of the unsolved case ten years ago, and a question that sent shivers down her spine: "Do you really think that thing is over?"
