Yun Qingya transmigrates into the body of a cannon fodder character in a period romance novel called Sweet Military Marriage. In the original story, this woman shares her name with the ex-wife of the powerful male lead, Li Jingye, a third-generation military heir from an elite Beijing compound family. The marriage was arranged by their grandfathers after the original host's grandfather saved Old Master Li's life. The original host, manipulated by the Li family's adopted daughter Cao Zhizhi, behaved outrageously toward Li Jingye, especially after he missed their wedding to attend a secret military mission. When the Li family was falsely accused and exiled, the original host demanded a divorce and most of their assets, leading to her grandfather's death from rage and her eventual torture and murder by a second husband arranged by her stepmother. Yun Qingya arrives just before the Revolutionary Committee confiscates the Li family's property, determined to change her fate and protect the man she finds attractive.
Yun Qingya immediately reverses her stance, refusing to divorce Li Jingye despite the family's impending downfall. She reveals she possesses a spatial storage ability that traveled with her and urgently leads Li Jingye to his father's study. There, she discovers a forged letter accusing the Li family of treason and collusion with foreign enemies, planted by a resentful former lover. While Li Jingye reads the incriminating document, Yun Qingya locates a hidden secret room containing the family's substantial wealth in gold, silver, and jewelry. She transfers the assets into her space and disables the mechanism to prevent future discovery. When the Revolutionary Committee, led by Director Li Hong, arrives to search the residence, Yun Qingya confidently negotiates the terms of the search, forcing the officers to be careful not to damage property that might become state evidence.
Cao Zhizhi, the adopted daughter, attempts to sabotage the Li family by revealing a photograph of Grandpa Li with an overseas cousin, hoping to trigger charges of foreign connections. However, Yun Qingya exposes Cao Zhizhi's true motives, revealing that the adopted daughter had harbored romantic feelings for Li Jingye since adolescence and orchestrated the framing out of spite after being rejected. Li Jingye coldly dismisses Cao Zhizhi, stating he regrets his parents adopting her. With the treason charge averted but the overseas relative connection still standing, the Li family faces inevitable exile to the Northeast. Yun Qingya insists on accompanying them, refusing to let Li Jingye face the hardship alone. She also visits her natal family to retrieve items the original host had given away and recovers her late mother's keepsakes, securing financial resources for the journey. The Li family, grateful for Yun Qingya's intervention, accepts her decision to stay, and she begins to integrate into the family dynamic, earning the affection of Mother Li. As they prepare for exile, Yun Qingya and Li Jingye's relationship begins to shift from strangers to allies, with Li Jingye increasingly drawn to her competence and beauty.
