Pei Yunting is the beloved Second Miss of the Marquis of Zhen'an's residence in Yanjing City, renowned for her gentle temperament and hidden talents in martial arts and strategy. Despite her noble status, she possesses a rebellious spirit that occasionally leads her to disguise herself as a young man to explore the city. One evening, she visits Xiaoxiang House, the most prestigious pleasure house in the capital, where she is discovered by Yan Huaijin, the Third Prince. Yan Huaijin, known as the Little King of Hell, is a powerful imperial prince currently recovering from injuries sustained while investigating a major embezzlement case implicating high-ranking officials. He arrives at the brothel with urgency, having been alerted by Pei Yunting's guards, and confronts her in a private room.
The confrontation reveals the depth of their complex relationship. They are childhood sweethearts who have grown up together, sharing an unspoken understanding and deep bond. While Yan Huaijin is furious about her reckless behavior, he is also concerned for her safety. During their time in the private room, they accidentally hide behind a screen as another guest, Lord Liu, engages in intimate activities with a courtesan. Yan Huaijin realizes Lord Liu is connected to his investigation and uses the opportunity to extract information, keeping Pei Yunting close by his side throughout the ordeal. The experience leaves both of them flustered and aware of their growing attraction, though neither explicitly acknowledges it.
The following days see Yan Huaijin suffering from vivid dreams about Pei Yunting, while she experiences prophetic dreams of a wedding. Their relationship is tested when Yan Huaijin is injured again while pursuing the embezzlement case, which leads to the discovery that Assistant Minister of Justice Li Rao is involved. Li Rao is a protégé of Prince Yi, the father of Commandery Princess Nanping, who harbors a secret admiration for Yan Huaijin. The political landscape is tense, with the First Prince Yan Huaize holding significant power and the Second Prince being too ill to compete. Pei Yunting finds herself caught between the two princes, particularly after a chance encounter with Yan Huaize during the Mid-Autumn Palace Banquet.
At the banquet, Pei Yunting displays her literary talent, reciting a poem that earns the Empress's praise. However, she feels trapped by court etiquette and longs for the freedom of the city streets. Yan Huaijin, noticing her restlessness, orchestrates a plan to sneak her out of the palace. He asks the Empress for permission to take Pei Yunting away, claiming he wishes to protect her. The Empress, aware of their close relationship and Yan Huaijin's feelings, agrees to cover for them. Pei Yunting is led to a private room where Yan Huaijin reveals his intention to take her out to see the festival streets, fulfilling a wish she had expressed earlier. The story concludes with the two boarding a carriage together, leaving the palace behind to experience the vibrant life of Yanjing, marking a significant step in their relationship as they navigate the dangerous political intrigues surrounding them.