April 1950, Lin'an. A murder case occurred in the back alley of a teahouse, and the identity of the deceased remained a mystery. Three cases of arson, theft and disappearance came together, which were both false and true. Zhao Jianfeng followed Lao Qian for an in-depth investigation, covering docks, shipyards, pharmacies, hospitals, and train stations. During the visit, the words of the masses, the old ashes in the archives room, the silencers in the woodshed, and the numbers in the secret telegrams pieced together a larger conspiracy bit by bit. In Lin'an in April, the whistle at the train station is about to sound, and there is an undercurrent surging beneath the water. Zhao Jianguo must find the full picture hidden under the water in the fog before his opponent takes action.
It's okay, the details are detailed