Accidentally Swapped Marriages with My Legitimate Sister

Shen Youran is the third daughter of the Minister of Revenue, known in the capital for her beauty but also for her lack of refinement in the traditional arts. She lives with her father and stepmother, Wei Shi, while her elder sister, Shen Yunshu, returned to the capital two years ago after spending a decade with their mother in Xunzhou. Yunshu is poised, intelligent, and deeply protective of her younger sister, having previously blocked a marriage between Youran and a deceitful nobleman named Lin Wulang. The story begins when Yunshu is set to meet Pei Huaijin, the eldest grandson of the influential Pei family, for a matchmaking encounter at Rainbow Bridge. However, shortly before the meeting, Yunshu suffers an allergic reaction to rouge, causing her face to swell with hives. Unable to cancel the meeting without jeopardizing the alliance, she persuades a reluctant Youran to impersonate her. Youran, motivated by the promise of skipping her daily studies, agrees to take her sister’s place.

At the bridge, Youran stands in for Yunshu while Pei Huaijin observes from below. Though Youran struggles to maintain her sister’s dignified demeanor and is distracted by the scent of street food, Pei Huaijin is charmed by what he perceives as a unique blend of serenity and liveliness. He accepts the match, and the Pei family formally proposes marriage to Yunshu. Meanwhile, Youran’s own marriage prospects are considered, with a match proposed to Liang Liulang, a martial artist. During a temple fair to facilitate this second introduction, Youran encounters Pei Huaian, the frivolous and wealthy seventh son of the Pei family. Wearing a Nuo mask, Huaian impulsively buys her a clay figurine and lifts her veil, causing Youran to flee in embarrassment. The Liang family, witnessing the interaction, misunderstands the situation and cancels the engagement, leaving Youran’s marital status uncertain.

At a birthday banquet for Old Madam Pei, Huaian recognizes Yunshu as Youran’s sister and attempts to deliver the figurine as an apology, but Yunshu, aware of his reckless reputation, coldly refuses. The narrative then introduces a secondary conflict involving Yunshu’s past. Her mother has remarried Lu Zhun, the prefect of Xunzhou, and Lu Yi, her stepbrother, has arrived in the capital. Lu Yi harbors improper desires for Yunshu and has been obstructing her attempts to change her surname to escape his attention. Yunshu had secretly agreed to marry Pei Huaijin to secure her independence and flee the Lu family’s influence before her mother’s household arrived in the capital. Upon learning that Lu Yi has met Youran and discovered her location, Yunshu becomes terrified that her secret engagement will be exposed.

Fearing Lu Yi’s interference, Yunshu retreats to the Pei family’s country estate under the guise of accompanying Old Madam Pei to escape the summer heat. She leaves Youran behind in the capital, assigning a maid to enforce a strict regimen of study and discipline in her absence. Youran, initially resentful of the punishment, eventually encounters Lu Yi again in the entertainment district. He reveals that their mother is arriving in the capital soon, a news that stirs complex emotions in Youran, who has longed for her mother’s affection. The story establishes a dual trajectory: Yunshu’s desperate flight from her stepbrother’s obsession while navigating the complex politics of the Pei household, and Youran’s transition from a carefree, spoiled girl into a young woman facing the consequences of her actions and the looming arrival of her mother’s family. The central tension rests on whether Yunshu can successfully marry Pei Huaijin before Lu Yi uncovers her secrets, and how Youran’s encounter with the Pei family’s younger branch will alter her own fate.