Shen Qingtang transmigrates into a historical domestic-strife novel, becoming a maidservant who is supposed to be poisoned to death in Chapter Three. The first thing she does after opening her eyes is confirm that she is dead. The original owner really was poisoned. As a modern forensic pathologist, she knows her judgment is sound.
Using her forensic knowledge, she solves her first case and rises from a maidservant to a free-status servant. In the second case, she joins the Jingzhao Prefecture. In the third, she discovers that every victim is someone in the novel whose ending was never written. Someone is "cleaning up" this world.
And the heir of this world, a man who is supposed to marry a proper wife and have nothing to do with a maidservant, hands her a note in the dead of night. It reads: "This well was sealed three years ago."
The Zhou family gives her a box of pastries, with a note tucked underneath: "Do you know what's in the box?"
The name on the last page of the ledger is his.
