Episode Summary
Consort Hua switches the marriage alliance candidate from Yin Shujun to Yin Liangjun, forcing Shujun's family to quickly find her another match. Jian Mingshu decides to stay and investigate the rumors surrounding Shujun, believing her innocent. Shujun confesses she loves Jiang Wenrui and let the rumors spread to avoid the alliance. However, Jiang Wenrui cruelly rejects her due to her tarnished reputation. Suspecting Yin Liangjun orchestrated everything, Mingshu, Lu Chang, and Song Qingzhao gain Prince Rui's approval to delay the alliance. They set a trap by faking an affair between Lu Chang and Shujun, but the plan backfires when Shujun faints and Lu Chang is lured into a room and drugged.

Spoiler Alert
Serendipity Episode 6 Recap & Spoilers: The Plot Thickens!
So, things kick off with Consort Hua deciding to switch up the marriage alliance – Yin Shujun is out, and they need another Yin daughter. This sends First Madam Yin (Yin Da Furen) into a panic. Not only is she worried Shujun will never get married now (ouch!), but picking between the other daughters, Yin Liangjun and Yin Xianjun, feels like a minefield. Grand Preceptor Yin (Yin Taishi) steps in and picks Yin Liangjun, praising her "dignified and virtuous" nature. The catch? If Liangjun marries into the alliance, eldest sister Shujun has to get hitched ASAP, preferably far, far away from the capital to avoid any more drama. Double ouch.
Meanwhile, our girl Jian Mingshu is summoned by Madam Yin. She gets the hush money she was promised earlier, with Madam Yin basically saying, "Sorry, kid, my hands are tied." But Mingshu isn't about to just take the money and run. She's convinced Yin Shujun wasn't the one who wronged her (referencing whatever trouble landed Mingshu in this spot). Yeah, the silver is tempting (and she feels a bit guilty about wanting it when talking to Lu Chang and Song Qingzhao later), but her conscience wins out. She points out that even though Shujun wasn't exactly nice to her, she doesn't believe Shujun, with her upbringing, would stoop that low. Plus, the nasty rumors about Shujun were just hearsay – no one actually saw anything. Mingshu feels strongly that women need to stick together, especially when things get tough. Lu Chang, remembering how Mingshu had to take charge after her own mother died, sees a parallel with Shujun's current plight and agrees to help her investigate. Go team!
The marriage pressure on Shujun gets real, fast. A matchmaker shows up, but the potential groom is some dude over 40 looking for a second wife (a "filler wife," as the text puts it). Madam Yin is furious and throws the matchmaker out. Shujun, hearing that Liangjun is now the alliance candidate, is actually relieved. Still, pretty much everyone in the household, except Mingshu, is whispering that she brought this on herself.
Shujun is surprised Mingshu hasn't left. Mingshu then confronts her, revealing she talked to Shuang Yan and knows Shujun secretly switched the Geng Tie (those important marriage compatibility cards). Mingshu cuts to the chase: "Is there someone you already like? Someone named Jiang Wenrui?" She even produces the embroidered pouch with "Rui" on it that Lu Chang and Song Qingzhao found earlier. Mingshu lays it on thick, reminding Shujun that even without the alliance, she has to marry before Liangjun does – maybe even to that 40-year-old widower!
Elsewhere, Third Madam Yin (Yin San Furen) and Yin Xianjun seem perfectly fine with Yin Liangjun getting the alliance spot.
Cornered, Shujun finally confesses to Mingshu. She and Jiang Wenrui fell for each other, but then the alliance mess happened. She admits that while she didn't start the rumors about herself, she didn't deny them either because they helped her dodge the unwanted marriage. Now, she begs Mingshu to tell Jiang Wenrui to propose quickly!
Song Qingzhao hears the whole story and wants to report the truth to Prince Rui (Rui Wang). Mingshu quickly stops him. Yes, Shujun messed up, but Mingshu understands her desperation. Lu Chang pipes up, recalling Mingshu's own bold move back in the day – the "Bang Xia Zhuo Xu" (literally "grabbing a son-in-law from the list of successful exam candidates") – figuring she must have felt similarly cornered then. Persuaded, Song Qingzhao agrees to hold off reporting to the Prince for now, but warns them time is running out.
Song Qingzhao arranges a meeting with Jiang Wenrui, Mingshu, and Lu Chang. Mingshu presents Shujun's heartfelt letter asking him to propose. And guess what? Jiang Wenrui totally bails! He claims her reputation is too damaged now and even lets slip he's been secretly checking out other marriage prospects. He storms off in a huff... only to open the door and find Yin Shujun standing right there, having heard every single treacherous word. Devastated, Shujun leaves, while Mingshu, Lu Chang, and Song Qingzhao are left fuming at his cowardice.
Back at the Yin mansion, Shujun is an absolute wreck, feeling like her life is over. She actually grabs a knife, intending to end it all. Mingshu wrestles it away, trying to snap her out of it. "Someone is manipulating things behind the scenes!" she insists. "We have to find out who!" They talk for a long time. Later, when Mingshu gets back to her room, Lu Chang and Song Qingzhao notice she got slightly injured grabbing the knife.
Then, a clue! Mingshu spots a servant washing shoes stained with tung oil – shoes belonging to Yin Liangjun's maid! Yin Xianjun confirms that Liangjun had visited her courtyard recently, using the excuse of borrowing a hand warmer. Suddenly, it clicks: Could Yin Liangjun have orchestrated this whole mess – the rumors, the sabotage – just to snag the alliance that Shujun didn't even want?
To buy more time, Song Qingzhao takes Lu Chang to see Prince Rui. The Prince is engrossed in a tricky chess problem. Lu Chang cleverly uses the opportunity to impress the Prince with his insight, subtly recommending himself. They ask the Prince to postpone the alliance so they can uncover the truth, appealing to his reputation as a wise ruler pushing for reforms. Impressed, Prince Rui agrees to the delay and notes Lu Chang's potential, especially with the Imperial Exams coming up. Mingshu is super grateful to Lu Chang afterward, calling him a great "older brother" type (aww!).
Now, for the counter-attack! Mingshu and Lu Chang decide to lay a trap. They start acting like Lu Chang and Shujun have something going on, hoping to bait the real culprit. Yin Xianjun "overhears" (likely part of Mingshu's plan?) and thinks she's uncovered their secret affair, planning to expose them publicly during the upcoming betrothal ceremony.
The episode ends on a cliffhanger: Yin Shujun is tending to her plants when she suddenly faints. At the same time, Lu Chang is told Mingshu got hurt in the study room. He rushes over, but the door slams shut behind him, and he starts feeling dizzy and disoriented.