In the thirteenth year of the Apocalypse, the Mu family's Baigong Bureau was plotted by the stepmother Liu and her uncle to offer her to the prince in exchange for an official position. At the critical moment, Mu Wei, the head of the bureau, worked hard to protect his grandfather and father all his life. He found Xiao Jue, the idle prince of Jing, and agreed on a marriage contract with a piece of paper - she got the protection of the palace and protected the bureau, and he used his position as princess to avoid the palace's marriage.
Under the contract, she used construction arithmetic to improve looms and waterwheels, and relied on her craftsmanship to break the secrets of the harem and solve the industrial crisis; while he hid behind the scenes, using the power of the palace to block the prince's pressure and investigate the undercurrents in the court. From the fight in the back house where materials were cut off and rumors were spread, to the whirlpool in the court involving the fight for the legitimate son and the discovery of one's life experience, the two went from being alienated as allies to gradually becoming dependent on each other.
When the Baigong Bureau becomes a bargaining chip to win over the enemy, the doubts about Mu Wei's life experience gradually become apparent. This marriage that started as a transaction finally gave birth to true love on the road of protecting the industry and the country.
