Lin Wan, an ancient book restorer, went to Qingxixian alone to pick sycamore leaves on an ordinary late summer night and never returned.
Interpol Zheng Jie was ordered to investigate and set a seven-day deadline for himself.
The clues left at the crime scene seemed to have been carefully placed - the driving records of ex-boyfriend Zhou Jingming, the bloody clothes under the bed of secret admirer Chen Mo, and the name on the knife of colleague Zhang Ye. Each one pointed to a different suspect, and each one contained unexplainable flaws.
Lin Wan held a sycamore leaf in her palm. There is a deep nail mark on the back of the leaf, and tiny brass chips remain on the leaf tip.
Those were the last words she left to this world.
In seven days, Zheng Jie cleared away the fog step by step: his ex-boyfriend who was desperate, his colleagues who had no choice but to run away, and the real murderer who hid behind everyone and carefully laid out the frame-up.
No one is born a bad person, but everyone makes the wrong choice at a critical moment. And Lin Wan used her last sanity and strength to leave that tiny trace on that sycamore leaf, waiting for someone to see it, understand it, and come to the truth for her.
This is a story about obsession, cowardice, greed and tenacity, as well as a story about "how to leave a light in the darkness".
