Midnight Mystery Case

. There is a fatal code hidden in the radio signal at midnight. The murder in the secret room of Shen Mansion's study in Tongzhou, the locked doors and windows, the bloody "Analects of Confucius", and half a plum blossom petal, point all suspicions towards the debt-ridden second son. However, when Su Yan's fingertips brushed over the scratches on the door latch and the word "Lin" on the jade pendant, he discovered that the crimes committed late at night were never temporary - the scientific research fraud ten years ago, the blackmail that lasted for many years, and the broken green calyx plums all woven into a web of revenge in the shadow of midnight. The truth is hidden in the old songs played on the radio. When the last note falls, who is the real mastermind?