Work Text:
So, ~8 years after the Chiyan case, Jingyan meets MCS and falls In Love and takes him back to Jinling and makes him his consort and has hearts in his eyes and just loves him to pieces. He knows MCS is the chief of the Jiangzuo Alliance, but MCS is probably still going by Su Zhe just to keep it from being common knowledge and all that.
And Jingyan is very happy and totally "knows who he married" so after a while of seeing that MCS is not gonna tell him that he's got plots going on and just assumes Jingyan will not notice random members of the Jiangzuo Alliance coming and going, or all the messenger birds, Jingyan tells MCS, "honey, I love you, if there's anything you need from me for your plots, just let me know and I'll do them or get them for you, I won't even ask you why if you don't want me to, but you don't need to try to maneuver me to get what you want, you just have to say."
MCS, internally: Jingyan, what the fuck, don't trust me.
MCS, out loud: okay, your highness.
But MCS is not exactly eager to tell Jingyan any of his plans, he wants to protect Jingyan and all that, plus Jingyan's lying face is a bad face.
There is one time when MCS decides to test just how sincere Jingyan was about that "I'll do what you tell me without asking any questions because apparently Jingyan joined the Jiangzuo Alliance without telling anyone??? or asking the chief??? did he think he just married into it??? jingyan, sweetheart, you're a prince, not one of my spies, what are you doing???? is this some kind of proof of devotion???? do you think I don't know you love me????"
But MCS does have one day where having Jingyan hover around in a public place, one very far away from any plotting, would be Useful, so he tells Jingyan to go visit his mom. Jingyan says it's not a day when he should be visiting his mom, but he'll try to get in, and if he doesn't, he'll wander visibly and maybe visit Commander Meng or something, Meng surely has nothing to do with any of this, right?
MCS does not blink.
Jingyan gets permission to visit his mom and has a nice happy visit and asks his mom to teach him to bake something nice for MCS, because Jingyan wants to make him a nice pastry for his birthday and Jingyan will need plenty of practice. Because 1) this is true, 2) this gives Jingyan a specific reason for visiting a lot, other than "wants to see mom", to give to anyone who is wondering why he is pushing to visit his mom, because Jingyan figures this is not gonna be a one-time thing, and he is so pleased that MCS trusted him with this and he wants to encourage sharing of important things within this marriage.
Mom offers an option of something with nuts, which Jingyan says no to, because MCS does not eat nuts. Because Jingyan noticed MCS being wary of specific nuts and then realized that, oh noes, my husband is allergic to nuts but doesn't want to say anything because that would then be a weakness known about the chief of the Jiangzuo Alliance. And so Jingyan's, like, turned his house nut-free without at any point telling MCS he was doing that.
Mom is really touched by this, but then also asks what Jingyan's been doing with all the hazelnut pastries she's sent him, and Jingyan goes shifty eyes and says he eats them in the garden and doesn't let anything touch MCS. But, uh, mom, if you could stop giving me those, so I can share with MCS, um.
So Mom starts teaching Jingyan important baking skills for impressing his husband, because Jingyan really struggles to find gifts that MCS likes and he's tired of having random gifts re-gifted to Fei Liu, like, he likes MCS's bodyguard and all, but sometimes a husband just wants his consort to keep his damn gifts. But if Jingyan gives him something to eat, maybe MCS will actually eat it?
Anyway, he lives in hope.
At some point in all of this, Lin Chen comes to visit and Jingyan goes "if this is your best friend, that explains certain things. Also can we talk about all the pigeons?"
Lin Chen: no, we cannot talk about all the pigeons, ask your husband.
But Lin Chen likes that Jingyan is on Team Make MCS Take His Medicine. Jingyan first endeared himself to the Jiangzuo Alliance folks by getting Doctor Yan to the side and asking if there was anything he could do to help, and when Doctor Yan said "can you get MCS to rest", Jingyan says "yep" and does it. Because MCS is kinda weak to the water buffalo tearful eyes of just wanting his husband to rest while he's coughing up blood, that can't be too much to ask, here I got you some new books and I'm going to read them to you so you don't strain your eyes and no, I'm not going anywhere and you can't make me. Oh, those noises? That's me and the entire army in my courtyard, now sit back and rest, I'm going to read to you from whatever the hell this book is, and you're going to rest.
MCS grumbles at how his nannies have co-opted his childhood best friend and also his husband to their vile schemes of making him not push his body to the breaking point.
Fei Liu presents Jingyan with some nice flowers of acceptance, welcome to the family.
It's ~4 years after they got married when Jingyan hears about the Northern Yan sixth prince shenanigans and that the sixth prince gave all the credit to having the help of The Divine Talent Mei Changsu, Jingyan gets Suspicious and asks MCS if there's anything he should know about MCS conspiring in a different kingdom to get a disfavored prince appointed as crown prince. MCS: "erm".
Because Jingyan has been steadily rising in court, not suspiciously fast like in canon, but slow and steady, without him actually doing anything, while his older brothers slowly lose ground. and Jingyan hadn't thought too much of it, if he'd thought MCS had anything to do with it, he just shrugged and was like "well, my husband loves me and is nice to me and wants to do good things for me." but that is on a different level than conspiring to make him crown prince, especially without letting him know.
And MCS just puts it all on the table, well, some on the table. He tells Jingyan that he knows it's not really something Jingyan wants, but look at the crown prince and Prince Yu, would *you* want them to be Emperor? And then MCS says, looking at the candidates, who would *you* pick? And Jingyan struggles with it and then asks MCS how long he's been planning this. MCS non-answers by saying it wasn't until he got to Jinling and saw closer-up what the Crown Prince and Prince Yu were like that he decided to take this path. Jingyan pushes and says no really at what point did you decide you were gonna make me emperor. He pushes until MCS admits it was before they met and Jingyan keeps pushing, okay, how *long* before we met, and Jingyan keeps pushing on dates and stuff and eventually goes "what do you mean, after you heard about Prince Qi, I know you're younger than me, how old were you at the time, 16? how did you even hear about me out in the jianghu? ...DID YOU KNOW XIAO SHU"
MCS says he did not.
Jingyan calls epic bullshit in his head, how the hell else does a random teenager nowhere near the capital decide 1) that random seventh prince no one's ever heard of is a good dude, and 2) let's make him emperor since he's the best choice now that Prince Qi is dead. "For fucks sake," Jingyan does not say, "at the time of the Chiyan case, my youngest baby brother was barely born, who the hell are you that you decided to mess with this?"
But Jingyan is not gonna get answers from MCS about it, so he decides to ask MCS's entourage. He picks Li Gang, because of all the folks who come and go, Li Gang is generally always there and, unlike Fei Liu, asking Li Gang where he was 12 years ago will not give the answer of "I was 4 years old". Jingyan pushes Li Gang about his whereabouts 12 years ago. Li Gang first goes "uh, I don't know" and flanicks and then settles on "Langya Hall. I was definitely in Langya Hall." Jingyan: "who was with you in Langya Hall?" "Um." "Why were you in Langya Hall?" "Um." And then Jingyan flat out asks him "do you know Wei Zheng" and Li Gang just blanches for a moment. He was not expecting this kind of interrogation today from his chief's husband, okay, he was not prepared for these shenanigans, Marshal Lin, please don't be mad at me.
Jingyan pulls in Lie Zhanying and says, hey, how many Jiangzuo Alliance folks do you think we have hanging around my army? Zhanying can't give an exact number but gives an estimate on the officers, and as for the enlisted men, he's not sure, but he knows it's gone up a lot since Jingyan married their chief. Jingyan asks if the JZ Alliance folks act in a way that gives them away, and Zhanying ponders and says, well, some of them give themselves away with how batshit they are to protect you, that's how I noticed the first time, remember that time we didn't know there was an ambush but one guy kept putting himself right where he'd be in the middle, but wouldn't say why? Totally a JZ Alliance dude keeping secrets. Zhanying can tell them apart from all the other spies because those spies are out to get Jingyan for various reasons, whereas MCS's spies just want to keep him safe.
Jingyan: okay, and how long would you estimate they've been around?
Zhanying: um. since before you got married.
Jingyan: how long since before I got married?
Zhanying isn't sure, because usually they aren't blatant enough to draw too much attention and they aren't trying to undermine Jingyan, just gather info and protect the prince. Jingyan gets the impression it has always been this way, or at least, for a while, and wtf, how long has all this been going on, how could this have been going on for long, what the fuck kind of planning is this, did this all start right after Prince Qi died, how could that be the case, there's no way that's true, wtf.
And so Jingyan comes to the conclusion that there is no teenager on the planet who would decide Jingyan should be Emperor in place of Prince Qi in the aftermath of the Chiyan case, and have wanted to protect him for a long time, or have any way to accomplish it ten years ago, except for Lin Shu. And therefore ergo MCS is Lin Shu and has been keeping it from him. And if he's been keeping it from him this long, clearly he's not gonna be the one to take the first step. ...Or maybe he's wrong and he's not Lin Shu? (Outtake: Jingyan going "hmm... that would explain why their dicks are exactly the same.")
But Jingyan has a great idea on how to find out for sure. He grabs a nice pretty gift he was gonna give MCS, idk, I was thinking a nice chain thing for his hairpiece? Yujin has one in a scene, I noticed. But IDK anyway, some kind of nice jewelry. And he also grabs the pearl. And he goes to MCS and lays them out in two boxes and says, hey, pick one. MCS opens the jewelry and pretends it's the nicest thing anyone ever gave him, while Jingyan rolls his eyes, because he knows how to give MCS pretty gifts and how MCS is mostly meh about them all. And then MCS opens the box with the pearl. And he wets his lips a few times. And then he says, "I get both of them, this one was already mine, you got it for me."
Jingyan: LIN SHU WERE YOU EVER GONNA TELL ME.
MCS: ...Wasn't planning on it.
Jingyan: :( :( :(
MCS: Look, honey, you are a really bad liar and I'm a traitor sentenced to death.
But Jingyan gets (most of) the plan now, that MCS came here to get rid of Xie Yu and Xia Jiang and also convince the Emperor to overturn the Chiyan case, and of those three objectives, the third one is the fucking hardest and MCS isn't 100% sure on how he's gonna handle that one.
Jingyan: okay we wait until I'm Emperor and I overturn it.
Just completely ignoring how hard it's gonna be for him to become Emperor, but since there is a specific goal now to achieve, that makes it a lot more palatable. Like, yes, I will become Emperor, because that is a necessary condition to clearing everyone's names, okay, let's do this thing.
MCS: we will fucking not wait until you're Emperor, it's gotta be Uncle Murderer
Jingyan: Um. That's gonna be harder.
MCS: *roll eyes* Now you tell me.
But now Jingyan is on board with MCS's plan, even if MCS won't tell him most of the actual details to Protect Him. And Jingyan is increasingly busy anyway, since MCS is about to get the crown prince demoted. Although maybe here MCS goes after Prince Yu first, since there's no need to pretend to be working for Prince Yu to undermine both him and the Crown Prince, MCS has just been yanking on their support systems for four years now and is watching it all go timber while Jingyan builds himself his own team of people who are not on teams and trying to get rid of corruption and stuff like that.
Eventually it becomes exceedingly obvious that Jingyan is not just That Lucky, that he is doing something and has a strategist, and that's probably around the time that word gets out that Jingyan's random jianghu consort Su Zhe is actually Mei Changsu, the dude who just had success with the Northern Yan succession stuff. "This isn't fair, he went and got the divine talent on his side four years ago, how am I supposed to compete with that", the crown prince doesn't say, and then tries to have MCS assassinated because, hey, if he doesn't work for him, he shouldn't get to work for anyone.
Jingrui's birthday is probably around this point as well. So as far as other people are concerned, the Crown Prince gets Xie Yu to use his own jianghu folks to hit at MCS, and then MCS fucking nuked them in retaliation.
(As far as Nihuang getting married stuff, maybe that happens the same way? Also I think Nihuang took one look at Su Zhe The New Consort To The Seventh Prince, thought "what random dude would marry this water buffalo when he could be hanging out in the jianghu? probably someone with an ulterior motive", has a moment of suspicious, then it clicks and she goes "oh, right, Lin Shu would totally do that, he absolutely would delude himself that this is a good idea because he wants his best friend back", and after that, she is BFFs with Jingyan's new consort, and Nihuang and Jingyan's friendship gets back a little bit to how it was when they were kids, except that Nihuang knows that Lin Shu is there, too, and Jingyan does not. But with the rape plotline, maybe Liyang was able to warn Nihuang directly or maybe there were other avenues, anyway, that all gets resolved without Nihuang being raped or being forced by anyone to marry anyone she doesn't want to, either by Consort Yue or the Emperor)
(there is the amusing thought, though, of that since Yujin and Jingrui both made it to the later stages of the contest, that Nihuang marries Yujin-protege-to-Prince-Ji-you-know-the-one-brother-of-the-Emperor-who-managed-to-survive and just, like, eats him alive and continues to be exactly as she was, except she's got a husband at home. And is now the Empress's niece-in-law. And pretends to be on Prince Yu's side for the sake of the plotting.)
(also, like, about that whole Prince Ji thing... where the Emperor says "do you think Jingyan wants to be crown prince" and Prince Ji says "yeah, sure, all princes do" and the Emperor just turns on him "what? all princes? even you?" and prince ji sees, like, his entire family tree pass before his eyes and goes "no! not me! I'm your little brother! I'm not one of those! I meant your kids! I entirely meant all your kids!" like, what the fuck Emperor Asshole. Also, wow, good on you Prince Ji, the sole survivor of all of that. Well, you and Marquis Yan. You are the only ones not dead and murdered by the Emperor. Good job. Every single time he's around the Emperor, you can just see him trying to get the fuck away, like with the whole Xia Jiang thing, that is one guy who does not want to still be there. That is a guy who knows exactly how big a blast radius gets when his brother explodes.)
Jingyan isn't happy about destroying Jingrui like this, but it helps that he can tell that MCS is also anguished about it. He can't delude himself that MCS is some kind of hard evil ruthless strategist when he's seen MCS cry about it. Neither of them are very happy about it, but MCS was like "this is the way we're doing it, unless you have some kind of better way of destroying Xie Yu", and then MCS, like, flashbacks to Meiling and is set on the course. They need to separate the Zhuos from Xie Yu so they can use that testimony to peel back some of the Chiyan plots that happened and they need to get rid of a pillar of the crown prince's support. It hurts Jingrui, but also gives him a brand new family and hey, what does a man with two families want for his birthday except yet another family? It's only logical.
They probably still get Xie Yu to write a confession and give it to Liyang and then he gets sent to a penal colony and then they kill him there when it's time for his testimony to be public.
For Xia Jiang, I don't know. I think he still allies with someone to go after Jingyan, whether it's Prince Yu or someone else or by himself, because Jingyan is gonna threaten his power base just like Prince Qi wanted to. He might still grab Wei Zheng, but in this situation, Jingyan trusts MCS and also Xia Jiang definitely can't just grab MCS and interrogate him, and if Jingyan defends his consort, that is not a suspicious thing to be doing. So the utility of grabbing Wei Zheng would be to reminder the Emperor that, oh hey, remember the whole Chiyan thing? And how Jingyan kept defending all of them? And how that is Wrong for Jingyan to have done that? And that if you ask Jingyan, he will 100% say Prince Qi and Lin Shu were innocent? So clearly Jingyan is not someone who should be made Crown Prince because he's not a good kid.
Except maybe by this point, the Emperor's gotten rid of the former Crown Prince and also Prince Yu and is like, "um, I'm kinda running out of sons here" because sure, he's got 9 sons. Except he had one of them killed. And two of them banished or whatever. And one of them is a child. And one of them didn't survive infancy. And another one of them is apparently too sick to do it. That leaves Jingyan and that sixth prince who has kids of his own and isn't apparently ambitious, says MCS, and there's gotta be one more son, I did actually count in the mourning-for-the-grand-empress thing, and there's definitely one more random prince? idek. But there is honestly an opportunity for the Emperor to realize that he's doing some kind of process of elimination bullshit on who the crown prince is gonna be, and by "elimination" he means "killing his sons"? Whatevs. Maybe the Emperor is planning to start a whole new game of "pit the princes against each other for favor" with Jingyan and idk what the sixth prince's name is. And maybe the sixth prince isn't ambitious in the same way that Jingyan wasn't ambitious? so he'd become ambitious if someone convinced him there was a point to it?
IDK, the point is, Xia Jiang probably does still push the Chiyan issue, and maybe by this point, Jingyan just turns to him in front of the Emperor and deadpans, "oh, right, I remember that time you had someone forge letters from Nie Feng, good times, good times. Hey, Dad, remember how we got a confession from the guy who killed the one who did it? And remember how Xie Yu confessed also? And I'm the one who is wrong for seeing through your conspiracy? Uh huh."
Which the Emperor does not want to hear, because this is not a guy who got told that his best friend was rebelling with his army on behalf of the oldest prince and thought "that sounds far-fetched". That's a guy who leaned into the plot and sure, he may not have been one of the conspirators, but he sure didn't stop them. And he's the one killing people over it, so, yeah, the Emperor does not want to hear this.
So he probably grounds Jingyan for a while, which, well, gives Jingyan quality time with his consort-slash-strategist. Who employs people who can fly over walls. So this is probably not the biggest problem they have right now. The biggest problem is freeing Wei Zheng. Who is being held as bait.
MCS: there's nothing I can do to convince you not to take the bait?
Jingyan: what are you looking at me for? he's your lieutenant. Don't you want to save him?
MCS: I hate you and every single one of your morals and principles. And I also hate that I love for your morals and principles...
They've for sure already turned Xia Dong by this point, because they know that Xie Yu not only forged letters from Nie Feng, he's also the one who got Nie Feng killed so he could bring his body back to his widow, ouch, and that Xia Jiang was involved in alllll of it. (I don't know if the yeti thing has happened by this point or maybe doesn't happen at all, idk, what's a timeline, what's a fic, this sure isn't a fic.) So there might be a way for Xia Dong to do something from inside the prison to get Wei Zheng out? Don't know.
They might find it easier to destroy the prison to get a prisoner out, than just to get the prisoner out. But to destroy it the first time around in canon, they needed Xia Dong to take the fall to the Emperor about it and it was a whole big thing. Maybe they can fake a prison break, in that they fake that it happens and they say they've got Wei Zheng? And then Xia Jiang has to bring Wei Zheng out to show the Emperor that, no, they didn't get him, he still has him, stop saying they rescued him? At which point, maybe they grab Wei Zheng from the actual fucking palace (hi, commander meng), or maybe they don't grab him at all, they have Wei Zheng do something to prove that he isn't Wei Zheng at all, and that this was all a plot by Xia Jiang to get at Jingyan because faction conspiracies, and the Emperor's like "what do you mean, Xia Jiang is doing faction conspiracies for someone else, he's only supposed to do that for me". IDK what Wei Zheng could do to prove he isn't himself. Maybe go up and down about his adopted dad and bring dad in to say where he found Wei Zheng, which was totally not the Chiyan Army, and here's a bunch of people to prove it? IDK IDK IDK.
IDK but they accomplish it without getting MCS poisoned.
So that's the two main Chiyan conspirators down. Time to go after the Emperor!
(As far as Qin Banruo and the Hua thing goes, I think MCS keeps chipping away at Qin Banruo's spies and all that, and I think events arrange themselves in a way that Prince Yu is already out of the picture by the time Xia Jiang tells Qin Banruo to open the letter? And riding out to deliver the letter to whatever place Prince Yu got exiled to and then having a dramatic comeback because Prince Yu found out who his bio-mom was, maybe not something that could be organized? Hell, maybe Prince Yu got executed, but probably not, it seems like if you wanna be executed, you gotta be suspected or guilty of actual armed revolt. Maybe Prince Yu was like "okay but my wife just gave birth and I'd rather not have everyone be killed???" like, who knows, I don't. But maybe Prince Yu doesn't find out, maybe he does. But I don't think there's a dramatic rebellion because of it. And maybe Qin Banruo just settled into a role of "try to undermine things at a lower level", possibly at a level too low for MCS to care about. Or maybe something else. Meh. As long as Jun Niang gets to go live her life happily without being forced back into spying that she didn't want to do, I'm fine with it.)
They probably still do it at the Emperor's birthday party? Since MCS never had that time to waste in prison taunting Xia Jiang, Xia Jiang never had his moments of connecting MCS with Prince Qi, and also he never found out about Extreme Makeover Bitter Flame Edition, so he doesn't connect that MCS = Lin Shu, so he never brings it up to the Emperor, so that's not a thing that's on the Emperor's radar. Lin Shu is completely 100% dead and no one has said otherwise or tried to make someone prove it by dying of poison.
So the Emperor throws a temper tantrum when Jingyan and MCS get Liyang to give him the confession and push him to reopen the case and everyone joins in, and Consort Jing gives him a speech about justice ffs justice is important what is wrong with you emperor dude.
Maybe the Emperor decides he wants a chat with his son-in-law the strategist who must have arranged all of this, such betrayal, but maybe he doesn't and just blames Jingyan for all of this. Because, hey, this is a Jingyan thing to do, right? Jingyan totally does stuff like this all the time. Because the father doesn't know the son :P
They get the Emperor to give in but it's hard, but then they clear the case, yay, and Jingyan asks MCS if he wants to switch his name back. And MCS says nope, Lin Shu can stay dead. Jingyan sadfaces but he's had a lot of years of getting to know his best friend again in this new face and he understand why MCS wants to separate his lives like that.
Lin Chen shows up as a Reminder Of Mortality, or, well, a Reminder Of Have You Been Taking Your Meds Mei Changsu. There's been a lot of excitement and Mei Changsu gets a thorough check-up from someone who doesn't really care that he just accomplished his life mission except to be concerned that he might not feel that he has a life still to live now that it's all finished. Lin Chen wants to go on vacation with MCS and magnanimously invites Jingyan to come along.
This is where Jingyan realizes that the clock has been ticking all this time but he's been too busy to hear it.
Jingyan: WAIT HOW LONG DO YOU HAVE LEFT TO LIVE WHAT DO YOU MEAN YOU'RE REALLY THAT SICK
MCS: ... Lin Chen, why.
Lin Chen allows that it's not that dire, since Jingyan has been sitting on MCS to make him sleep and eat and take his medicine and rest when he needs to and no one's been putting MCS in prison or making him stand in the snow, excellent nannying skills, you get an a+ on your exam. But he meant it about a vacation from all of this. He says it'll be good for him. Jingyan's like, okay but this better not be palliative care bullshit, I expect my husband to come back to me at the end of this, pinkie promise me that will happen.
He's also kinda worried about, y'know, MCS just plain leaving him. Because it's all done now? And this is what MCS came to Jinling to accomplish? And MCS has an entire life in the jianghu waiting for him if he wants to go back to it? What if this is it? What if MCS doesn't want to come back to this? If the only thing keeping MCS here is sentiment, is there enough sentiment???? What if his husband doesn't love him the way he does?????? Will he ever see MCS again???????
MCS: Lin Chen, go awayyyyyy.
Lin Chen: Nope, this is the best entertainment I've had in ages.
MCS: Ugh, fine. Jingyan, do you think I'm any better about letting people touch my things than I used to be? Of course I'm not letting you go. I'll come back to you and I'll make sure I live that long. And I'll bring you back great souvenirs. Do you want a pearl or something?
Jingyan: I just want you.
MCS: STOP BEING ROMANTIC, START GIVING ME DEMANDS FOR GIFTS
Jingyan: Okay, how about a completely different country in addition to the one you already gave me?
MCS: ...okay I can probably make that happen if you want--
And which point Jingyan just kisses him and finds a nearby bed and they have a lot of goodbye-you-better-come-back sex.
Also Jingyan probably tells MCS to take Tingsheng with him to give the kid some vacation experience, because they probably got him out earlier and he and Fei Liu are friends (and, like, I just can't with that plotline without getting very annoyed that the good solution is to save Tingsheng and two picked-at-random kids from slavery and then never go back and care about any of the other kids there, nope, Tingsheng is the only one who matters, once he's out of there, the fact that that treatment continues with other kids isn't a problem anyone cares about, which, sure, in character, but oh my god that bugs me so much, the only kid of value in that situation is Tingsheng because Jingyan has a personal familial connection with him. The rest of the kids, who cares).
Anyway, vacation all I ever wanted, vacation had to get away.
While that happens, I think fewer countries invade the country than the ~5 that did in canon, because there isn't as much internal strife going on since they probably got rid of the Crown Prince and Prince Yu much slower and more carefully and there wasn't that rebellion to show the neighbors that hi, we're Da Liang, we are full of internal tensions and ripe for invasion. But, sure, fine, war on all sides and/or a bunch of sides. Jingyan does not go riding off to the rescue because they're aware that if he leaves, the Emperor is gonna shove another one of his sons in as crown prince, because dad is Not Over It about the Chiyan case being overturned.
But they make it work with the generals they have, although afterwards Jingyan just looks at the state of the military and goes "well, I know what my NEXT PROBLEM to solve is" and maybe writes a line in his next letter to MCS saying "are you sure you don't ever want to be Lin Shu again? Because I need a general to shout at other generals, and Nihuang is getting a bit hoarse and wants some backup, but Meng is just not scary enough. LMK if you want to shout at some generals. Have fun at the beach!"
And somewhere on vacation, they find the magical cure for all of Mei Changsu's ills and they all live happily ever after.
As far as the form the happily ever after takes, that is Choose Your Own Adventure and also depends on, like, if having an Empress is a required thing, which I don't have any idea:
1) an Empress is not required, and part of the deal Jingyan made with his sixth brother when dad was encouraging infighting was, hey, congrats, once I'm the Emperor, you're the crown prince, and you better not undermine me or my husband/jianghu chief will cheerfully destroy you
2) an Empress is possibly required but it can be MCS for reasons, and also mpreg happens and MCS is healthy enough now that everyone doesn't go noooooooooo at the very idea
3) an Empress is absolutely required, and so Jingyan marries who he marries in canon but doesn't have a name given so I don't know what it is, and the new Empress and MCS get along perfectly fine and there are no problems, we are all friends here in this marriage with them and anyone else who Jingyan ends up marrying as well, I don't know how that works, Dad has enough concubines that I would have to freeze frame to count how many there are and that's not counting the dead ones
4) idek, Jingyan marries Nihuang, if she didn't marry Yujin above, and she goes to be a general in the next invasion, or maybe even this invasion and comes back victorious and marries the prince, and it's a nice fun happy Childhood Friends Are Now All Married To Each Other And Running The Country situation, especially because, well, no one ever did dissolve the engagement between Nihuang and Lin Shu, so really, we're just doing this so we don't have to do any paperwork to avoid it.
But for sure Lin Chen keeps sending Mei Changsu a lot of snarky commentary via pigeon.