Yu Yang, a merchant woman from Jiangnan, enters the capital carrying a marriage contract, only to be met with cold indifference from her cousin at the Grand Duke's estate and mockery from the legitimate daughter, as the entire household looks down on her merchant background. She simply takes things as they come, taking the handsome "guard" hiding in the dark chamber under her wing, teasing and bossing him around a hundred ways in the side hall's dark room, enjoying herself recklessly. It is not until her cousin's imperial marriage decree is issued that she asks for the guard, only to find out that the other person is actually the current crown prince. She flees overnight back to her hometown, only to be cornered halfway and dragged back to the Eastern Palace by the crown prince, turning a mistaken flirtation into a lifetime of exclusive favor in the inner palace.