During the Xiankang era of the Eastern Jin Dynasty, the Wang clan of Langya, leveraging their aristocratic power, constructed an underground prison palace on the outskirts of Jiankang city, abducting commoner women to serve as their private slaves. Xie Qingyi, a talented woman from a humble background, was captured. Amidst brutal training, she secretly observed the workings of the Wang mansion and befriended fellow prisoners like the female knight Murong Xue. Despite enduring whipping, foot binding, and torture with instruments, they remained unyielding. They orchestrated an escape by exploiting the power struggles among the noble families. Ultimately, during a banquet night in Wuyi Lane, they instigated a riot, exposing the sins of the aristocracy and shaking the foundations of the clan's rule.

During the Yongle era, Princess Zhaoren, Zhu Qingyao, was imprisoned in the Imperial Prison due to her uncle's involvement in the Lan Yu case, a fabricated accusation. The banner officer, Hu Bao, was ordered to subject her to a special punishment, ranging from humiliating bondage to brutal foot torture. Amidst the alternating torments of stockings and bare feet, the princess transitioned from despair to awakening, engaging in a psychological game by observing Hu Bao's weaknesses. When the foot torture endangered her life, she utilized knot-tying skills learned in Ryukyu years prior to set a counter-trap, ultimately exposing the conspiracy of the Censor Xu Shizhen and overturning the verdict on the execution ground.