After her parents die, He Qingli loses her sanity and is taken in by the Marquis of Yong'an's household. Although she appears to be engaged to the marquis's heir, she is actually being used as a pawn by the household to seize the He family's fortune, enduring constant bullying and abuse. By chance, she regains her senses and gains access to a daily intelligence system. Pretending to remain foolish, she cleverly takes advantage of the protection of the Grand Princess Qinghe and the Emperor to gradually expose the household's wicked deeds and punish Lin Qingrou and Shen Zifei for their cruelty. She subsequently gathers crucial evidence that the Marquis of Yong'an colluded with a prince and embezzled military funds, helping the imperial court convict the household and confiscate its property. In the end, the Emperor adopts He Qingli as his daughter and bestows upon her the title of Princess Yong'an. With wealth and honor at her fingertips, she chooses never to marry and enjoys a peaceful, carefree life of luxury.