Chapter 94: Bureaucracy Will Protect Me
We start out the chapter with a quick side quest, as Wei calls in the Qiang tribes of the northwest to attack Shu from behind. They win a few early skirmishes, but eventually Zhuge Liang utilizes the winter snow to get their iron-armored wagons stuck in a moat, so they shrug and go home.
The Wei army is in real trouble at this point. Cao Rui has the realization that if Zhuge Liang was only kept at bay because Sima Yi was there to oppose him, then his only hope is to bring in Sima Yi again. And thus, Sima Yi gets his job back, with the recognition that Wei basically can't accomplish anything without him.
Around this time we hear from a character named Meng Da; this guy is in charge of a territory that lies on Shu's northeast border. He was originally allied with Shu, but he defected to Wei as part of the shenanigans back in Chapter 79 that ended with Liu Bei putting his adopted son Liu Feng to the sword. Problem is, Meng Da really only defected out of circumstance; Cao Pi kind of liked the guy so he kept him around, but Cao Rui doesn't have the same sentimentality.
Meng Da starts getting a little nervous about his continued employment and/or existence, so he writes to Zhuge Liang, offering to swap back to Shu and march his troops on the Wei capital while their armies are distracted in the west.
Even though this was kind of the same thing that Wei Yan suggested a couple chapters ago, Zhuge Liang is more receptive this time. This could be evidence of his mistrust in Wei Yan, but the book doesn't take advantage of this point in any way. Instead, Zhuge Liang responds by writing back, good idea, except they just re-hired Sima Yi so you're going to need to be super goddamn careful about this. Just lay low for a little while so he doesn't suspect you and then I'll send word.
Meng Da writes back, hahaha that guy's a joke, if he wants to attack me he'll need permission from Cao Rui and it will take an entire month to get the paperwork signed, I have so much time to prepare it's not even funny.
And Zhuge Liang stomps his feet like, that goddamn idiot, why don't people ever fucking listen to me, Sima Yi has imperial authority to destroy rebels so he sure as shit ain't going to wait an entire month to go wipe out Meng Da.
Long story short, Meng Da sure is surprised when Sima Yi turns up a week later. And with Meng Da dealt with before he became a problem, Sima Yi now has Cao Rui's full and unwavering trust.