During Ruoxi's stay in Yinsi's house, Yinsi falls in love with her. She initially rejects him but later agrees to marry him if he gives up competing for the succession to the throne. Since she is from the future, Ruoxi is aware that Yinsi's ambition will ultimately lead to his death in prison after Yinzhen becomes emperor.
After breaking up with Yinsi, Ruoxi's interaction with Yinzhen changes her unfavorable opinion of him, and she unwittingly falls in love with him. Meanwhile, Yinsi and his supporters, acting on Ruoxi's advice, frame Yinzhen for plotting against the crown prince Yinreng (Zhang Lei). Yinxiang steps forward to take responsibility and is ultimately sentenced to house arrest. After this incident, Yinsi realizes that Ruoxi is now romantically involved with Yinzhen. Yinreng is deposed after his criminal ways are exposed and is imprisoned for life. Kangxi then begins showing preference for Yinti and offers Ruoxi as a concubine to him. However, Ruoxi boldly defies the emperor's order, and as a penalty she is demoted to the laundry department.
Kangxi eventually dies of illness, and with military support from Longkodo (Zhao Jialin) and Nian Gengyao (Xing Hanqing), Yinzhen stages a coup and seizes the throne from Yinti to become the Yongzheng Emperor. Yinzhen then releases Yinxiang from custody and makes Ruoxi his consort. Ruoxi's happiness, however, is marred by Yinzhen's paranoia and his ruthless persecution of Yinsi and his followers. She is often caught between the rivaling factions of Yinzhen and Yinsi.
When Yinsi's wife (Shi Xiaoqun) tells Ruoxi that Yinsi acted against Yinzhen years ago because of her advice based on the knowledge of the future, she is shocked, and her despair causes her to miscarry Yinzhen's child and is unable to conceive again. Enraged, Yinzhen blames Yinsi and his wife, issuing an edict forcing them to divorce, which leads her to commit suicide. Ruoxi fears Yinzhen's punitive actions against his brothers and confesses the truth to him and Yinxiang. Yinzhen is stunned when he understands why Yinsi plotted against him and starts treating Ruoxi coldly. Ruoxi is unable to withstand the mental stress and asks Yinti to help her leave the palace. Yinsi knows that Yinzhen will not allow Ruoxi to leave and decides to intervene. He discloses details of his past romance with Ruoxi, and an angered Yinzhen eventually agrees to let Ruoxi and Yinti leave the Forbidden City.
Despite Yinti's excellent care, Ruoxi's emotional anguish deeply affects her health, and she begs him to send a letter to Yinzhen, requesting to see the emperor one last time before she dies. However, a misunderstanding between Yinzhen and Yinti causes the letter to be thrown aside unread. Ruoxi struggles to stay alive, but after three days she concludes that Yinzhen's absence confirms that his love for her has ended, and she dies. When news of Ruoxi's death reaches Yinzhen, he rushes to Yinti's house, regretting his actions after learning that Ruoxi still loved him.
Back in 2011, Zhang Xiao regains consciousness in a hospital and is informed that she had been in a coma for weeks. She wonders if her experiences in the past were real or imaginary. After recovering, Zhang researches the Qing Dynasty era, only to find that history remains on its proper course, and there are no records on Ma'ertai Ruoxi. However, she later visits a museum where she recognizes some Qing Dynasty-era artifacts and sees a lady in a Kangxi Emperor portrait that resembles her. Meanwhile, a man who looks like Yinzhen also visits the exhibition and encounters Zhang Xiao but does not recognize her. Zhang is unable to control her tears as he walks away.
- Nicky Wu as Yinzhen, the fourth prince. He is destined to succeed his father as the Yongzheng Emperor and is Ma'ertai Ruoxi's true love. Nicky Wu also plays a mysterious 21st century man who meets Zhang Xiao in a museum weeks after she returns to her own time; he is speculated to be a present-day incarnation of Yinzhen.
- Kevin Cheng as Yinsi, the eighth prince. He is Ruoxi's first love interest and Yinzhen's rival for her affection as well as in politics.
- Yuan Hong as Yinxiang, the thirteenth prince. He is a bold, staunch supporter of Yinzhen and a close confidant of Ruoxi.
- Mu Tingting as Lady Ulanara, Yinzhen's wife and Ruoxi's rival in love.
- Zhang Lei as Yinreng, the crown prince.
- Ye Zuxin as Yin'e, the tenth prince.
- Han Dong as Yintang, the ninth prince.
- Annie Liu as Ma'ertai Ruolan, Ruoxi's older sister and Yinsi's second wife.
- Shi Xiaoqun as Gororo Minghui, Yinsi's wife.
- Guo Zhenni as Lüwu, Yinxiang's love interest.
- Chai Wei as Chenghuan, Yinxiang and Lüwu's daughter.
- Cao Xinye as Qiaohui, the Ma'ertai family's faithful maid.
- Ye Qing as Yutan, Ruoxi's best friend.
- Kang Mingtong as Yunxiang, a maid in the palace working with Yutan under Ruoxi.
- Cristy Guo as Minmin, Prince Suwan-Guwalgiya's daughter. She develops a crush on Yinxiang and befriends Ruoxi.
- Ba Sen as Prince Suwan-Guwalgiya
- Zheng Kai as Irgen-Gioro Zuoying, Minmin's suitor and eventual husband.
- Deng Limin as Li Dequan, a eunuch and personal attendant to the Kangxi Emperor. He was Ruoxi's benefactor and mentor.
- Zhou Yancheng as Wang Xi, a eunuch who is Ruoxi's best friend and Li Dequan's godson.
- Hu Zhonghu as Gao Wuyong, a eunuch and personal attendant to Yinzhen.
- Chen Jingyu as Yinzhi, the third prince.
- Wang Xiaodong as Yinqi, the fifth prince.
- Gao Sen as Li Guangdi
- Lian Teyue as Imperial Physician He
- Liu Yuxin as Gororo Mingyu, Yin'e's wife.
- Dai Chunrong as Empress Xiaogongren, the empress and mother of Yinzhen and Yinti.
- Liu Jie as Consort Liang, one of the Kangxi Emperor's consorts and mother of Yinsi.
- Ma Tianyu as Huang Di, Zhang Xiao's boyfriend in the 21st century.