At her birthday banquet, a pregnant concubine barges in and tries to usurp her rightful position as mistress of the household. Her mother-in-law protects Su Wanli with a slap. Everyone assumes she is merely the wife of a merchant, unaware that she is actually the legitimate daughter of the Duke Who Guards the Nation, living incognito among ordinary people. Her cold-hearted husband steals her identity, abandons their child, and climbs the social ladder through powerful connections. She decisively divorces him and settles the household accounts, wielding her secret guards to shake the imperial court. When the new emperor offers her the position of empress, she firmly refuses, accepting instead the title of Princess Who Protects the Nation and taking charge of the empire's wealth, choosing to live freely on her own terms.