The orphan Wen Nian has lived under the roof of the Marquis's residence for ten years, enduring endless contempt. When her cousin publicly smashes her betrothal gifts, Wen Nian seizes the opportunity and asks to marry the man instead. He welcomes her into his household with 108 sedan-loads of betrothal gifts. Their marriage is initially nothing more than a transaction, but Wen Nian earns the key to the library through her own abilities, gaining access to all the trade route account books. She devises a strategy to defeat the salt merchants and earns an exclusive personal seal, becoming Pei Shiyan's indispensable business partner. When he is summoned to the palace and leaves her a secret escape passage, she refuses to flee and spends the entire night writing a policy proposal on the salt trade. By coincidence, he presents the same strategy in the palace, and their ideas perfectly align. Once the crisis is resolved, the orphan who once lived at the mercy of others becomes the true mistress of the Pei household.