Eleven years after his older sister vanished, missing-persons reporter Chen Shu received a registered letter bearing her name. The yellowed paper contained a secret code known only to the siblings, while the new photograph enclosed with it had been taken just last month. Another sheet foretold that Zhao Qiming, the former head of the children's home, would die tomorrow night, and that his death would be ruled a suicide.
After Chen Shu reported it to the police, he discovered that his father knew what was hidden in the photograph. To prevent the murder and find out who sent the letter, he and detective Liang Zhen revisited the statements his sister had made before she disappeared. Who had sent the letter, eleven years too late? What had really happened on the night Chen Jianwei left Beiqiao?
