In the ninth year of Daye, Emperor Yang of the Sui Dynasty conquered Goguryeo for the second time, and a million troops were trapped under the Liaodong city.
Food routes were repeatedly cut off, military information was frequently leaked, and an ominous atmosphere filled the Zhengdong camp—someone was delivering news to Goguryeo.
Yu Wenshu was ordered to conduct a thorough investigation, but unexpectedly discovered a secret intelligence network spanning the thirteen states of the Sui Dynasty. The center of the net points to a mysterious figure codenamed "Xu".
At the same time, in a deserted village outside Luoyang City, a young woman with amnesia was rescued by an Orion. There is a strange copper charm hidden in her waist, engraved with cipher text that no one can decipher; she can write with her left hand, but the handwriting is a mirror image from right to left.
She had no idea who she was or why she was there.
But she knew one thing - someone was after her.
Behind the pursuit was a shocking conspiracy that could subvert the foundation of the Sui Dynasty.
When war is raging across the Central Plains and the imperial power is on the verge of collapse, who is secretly weaving this web of espionage?
It all started with a tampered secret letter.
