To find her sister, who has been missing for three years, Lin Jianlu ventures alone onto Wuyu, an isolated island shrouded in mist. A copper clasp her sister left behind, engraved with the character Yu, and a mysterious clue pointing to the forbidden Red Reef Bay pull her into a major smuggling case that has been brewing for a decade.
On Wuyu, seemingly ordinary landlord Chen Mo, reporter Jiang Che, who has concealed his identity, and the taciturn old woman who runs a dried-fish stall all have secrets of their own. Three copper clasps engraved with the characters Yu, Che, and Mo are the keys to the secret chamber of the smuggling organization known as Yu. They also connect the truth behind Professor Gu Wenshan's fall from a cliff and a reporter's disappearance ten years ago. Working with Jiang Che, Lin Jianlu must not only rescue her imprisoned sister from the underground prison at Red Reef Bay while evading the criminals hunting them, but also uproot the evil entrenched on Wuyu.
When the thick fog lifts and sunlight pierces the gloom over Red Reef Bay, long-buried justice is finally served, and the wronged souls swallowed by the waves at last receive the solace they have waited so long for.
