The Shen family, a prominent family in the south of the Yangtze River, was overturned overnight. Shen Qingtang, the legitimate daughter, survived the mountain of corpses and sea of fire and became the shopkeeper of the bookshop in the capital, just to find clues about the massacre that year. Xiao Jinhan, the king of Zhenbei, dominates the government and the public with his iron-blooded tactics, but during a mission to track down a "missing ancient book", he unexpectedly gets entangled with this seemingly ordinary female shopkeeper.
A broken manuscript that records the treasures and shocking secrets of the previous dynasty draws the two into a turbulent court battle. Shen Qingtang repeatedly solves strange cases by relying on knowledge from ancient books, but he does not know that he has become the most mysterious "chess piece" in Xiao Jinhan's eyes; Xiao Jinhan is getting closer to the truth step by step, but in his dealings with Shen Qingtang, he gradually exposes the scars and tenderness deep in his heart.
When the truth of the "anti-party case" was revealed, they discovered that the disaster of annihilation was not an accident, but a huge conspiracy involving the change of imperial power and old grudges. Shen Qingtang's identity, Xiao Jinhan's secret, the whereabouts of the previous treasure... All the clues are intertwined into an invisible web, tightly "locking" the fate of the two people at the crossroads of love, hate and intrigue. Are they each other's salvation, or the key to each other's destruction? In the turbulent situation in the capital, a game involving life, death and faith is slowly beginning.
