Pu Jinyu, a concubine's daughter, lived her first life as a substitute bride for her legitimate elder sister, Pu Wange. Raised in the countryside and brought to the Pu family only to be trained to impersonate her sister, she married into the prestigious Yan family under the name Pu Wange. For three years, she endured strict discipline from Nanny Wu and the manipulations of her stepmother, Madam Pu, who had orchestrated the deception to secure a political alliance. In her previous life, Pu Jinyu died in childbirth at twenty-nine, her heart failing after years of stress and emotional torment. After death, her spirit witnessed the truth: her elder sister was alive and had fled with her lover, while her mother had never loved her but viewed her as a disposable tool. Upon rebirth, Pu Jinyu returns to the summer afternoon of her third year in the Yan household, just moments after being reprimanded by Nanny Wu for relaxing her posture.
Determined not to die again, Pu Jinyu begins to change her behavior. She stops eating iced desserts, refuses to let Jingchun, her maid, coddle her, and confronts Nanny Wu with cold defiance. When Nanny Wu threatens her by mentioning her mother, Pu Jinyu offers her pear soup as a gesture of apology, but secretly poisons it. Nanny Wu falls violently ill with fever and rashes, her throat burned, and is removed from the Yan household under the guise of a sprained foot. Pu Jinyu also confronts Jingchun, revealing that she knows her maid betrayed her secrets to Nanny Wu, and asserts her authority by reminding Jingchun that she is now the legitimate wife and cannot be replaced.
Her husband, Yan Chiyun, a high-ranking official in the Zhenfusi, notices the change in his wife. On the night of the end of the month, when they are expected to consummate their marriage, Pu Jinyu initiates intimacy with unusual passion, engaging in multiple rounds. Yan Chiyun is surprised by her behavior but does not question it deeply. The next morning, he allows her to sleep in rather than attend to household duties, showing a rare moment of leniency. Pu Jinyu uses this time to plot her revenge, knowing that she must survive and eventually expose the truth about her substitution.
At a family gathering for her sister-in-law Yan Mingshu's return to her娘家, Pu Jinyu encounters Cheng Wenque, a friend of her younger brother-in-law Yan Huaixiao. His appearance reminds her of a sworn brother from her childhood, causing her to stare absentmindedly. Yan Chiyun notices her distraction and becomes suspicious, wondering if she knows the man. Despite his curiosity, he dismisses the thought, attributing it to her rare moment of inattention. Pu Jinyu, however, is lost in thought, recalling her past life and the people she lost. She resolves to use her knowledge of future events to protect herself and those she cares about, while carefully navigating the dangerous politics of the Yan and Pu families. Her ultimate goal is to survive, expose the deception that ruined her life, and reclaim her own identity as Pu Jinyu, not the shadow of Pu Wange.
