The portrait in the world-famous classic mystery novel," Sleeping on a Desolate Mountain ", referred to one of the suspense in the story. It depicted a portrait of a mysterious person. It was said that this person did not exist in reality, and only the portrait remained. This portrait became one of the clues in the story to guide the reader to make deductions and guesses. The reader could infer the plot and truth of the story by guessing the identity and background of the characters in the portrait.