During the Jian'an period of Daliang, the imperial power declined and the clans were divided. There is a mysterious shop called "Muyun Pavilion" in the capital. On the surface, it only does bookstore business, but secretly it is the largest intelligence dealer in the empire - dignitaries, princes and princesses, and even royal family members, all come here to buy secrets, sell information, and cut off their futures. The master of the pavilion never shows his true face. Everyone thinks that the boss behind the scenes is the resourceful "Mr. Muyun", but they don't know that "Mr. Muyun" is just a cover. The real master of the pavilion is the low-key and quiet staff beside him - the heroine Su Muyun. Su Muyun was originally the daughter of a prisoner of the imperial court. She was executed when she was twelve years old. She hid in the world incognito and built this intelligence network with her astonishing talent. What she wants is not revenge, but one day that everyone in the palace owes her a secret.
The purpose: to clear the grievances of the Su family and make the real murderer (the Queen Mother's remaining party) pay the price, while at the same time protecting himself and regaining his innocent identity.