Fogang, a southern seaport city, is humid and foggy all year round. The port, old city and new financial district are like three layers of a city that do not recognize each other. Female reporter Lin Zhi received a letter without a sender. The letter only contained one sentence and an address. When she arrived, a dockworker had disappeared, and the details left at the scene were very similar to the "Qingou Shipwreck" ten years ago. In that accident, her father Lin Yuanzhou was convicted of dereliction of duty and suffered infamy after his death.
Lin Zhi originally only wanted to investigate the first disappearance case, but found that a letter would appear every seven days, each letter announcing a new missing person. The missing persons appear to have no connection, but in fact they all had access to the Qingou's cargo records ten years ago. As the investigation deepens, Lin Zhi discovers that his father may not be a scapegoat, nor may he be a simple victim. Some people are using her letter to seek revenge, while others are using her to reopen old cases. When the tide in Fog Harbor recedes, what is revealed is not a corpse, but the sins hidden by an entire city.
