On the day when Su Yingying, the daughter of the loyal Chief Minister Su of the Cabinet, was married to the second prince Xie Yuheng, her family was massacred by Xie Yuheng and his troops on the grounds of the Chief Minister Su's alleged treason. Xie Yuheng thus ascended to the position of the crown prince. Three years later, Su Yingying returns to clear her father's name and uncover the truth behind the treason case. Teaming up with the seventh prince, Xie Yi'an, she disguises herself as Xie Yi'an's maid, Suying. Starting from the counterfeit banknote case, they discover its connection to Chief Minister Su and Xie Yuheng, prompting them to go deeper into the investigation. From initially being at odds, they gradually develop feelings for each other. Despite the dangers, they work together to get close to the individuals involved in the counterfeit banknote case. As they gradually uncover the truth, they expose Xie Yuheng's conspiracy to seize power and usurp the throne. It turns out that Xie Yuheng is not of royal blood. In order to seize the royal power, he makes the counterfeit banknotes to amass wealth, bribe officials, and establish an assassination organization called the "Vermilion Bird Pavilion" to eliminate dissidents. Because Chief Minister Su discovered that Xie Yuheng was the mastermind of the counterfeit banknote case before his death, Xie Yuheng ordered his men to steal Su's official seal and fabricate documents framing Su for treason.
