That's odd.  He's pretty sure that the first time he saw Wei-xiong call out to Lan Wangji, the other boy walked away immediately.  Huaisang doesn't think that anything has happened differently to cause that different reaction.  

Jiang Cheng is slightly distracted by other thoughts.  Still, it doesn't take him long to also notice the incongruous stare.

"...Wangji-xioong, are you still mad about last night? I didn't mean to break any rules, I swear! I wasn't trying to make you upset on purpose! I'm sorry, and you did break my Emperor's Smile, so can't we just be even?" He pauses and then smiles broadly. "I bet if you come with us I can find more ways to make it up to you!"

"...I must go to the library. I cannot accompany you."

"We can go to the library with you! Can't we?" He glances at his two companions, but doesn't wait for them to answer him. "There has to be some interesting spying-worthy things in there, even in such a boring Clan. - Ah, ah, not that you're boring, Ji-xiong, or at least - you sort of might be, but I think it's your clan's fault. I definitely believe that you could improve, and we can probably help. Everyone helps each other, see?"

"No."

The only thing worse than being in the library with Wei Ying right now would be being in the library with Wei Ying and Jiang Wanyin. Wangji turns around and attempts to resume escaping.

"I would love to go to the library, though," he says for possibly the first time ever.  He means it, too.  Where else to hide books?  Not to mention wanting to watch Lan Wangji.  Something must have changed to cause the last minute to go differently than what he remembers.

Nie Huaisang wanting to go to a library is one of the most absurd things Wangji's ever heard. Why does he have to even entertain this - 

Wangji can't actually bar other students from using the library just because he is struggling with self control. He doesn't generally believe that people should be kept from libraries. Now, unfortunately, it's too late to decide to go somewhere else.

"You are able to follow me," he grinds out, and then strides away.

He laughs excitedly and claps Nie Huaisang on the back. "There it is, that's permission for us! Well done, Nie-xiong. Our Twin Jade must have a soft spot for you, maybe he liked that canary after all. Shall we?"

"After you, Wei-xiong."

They want to go to the library?  Now he's sure something strange is going on.  Nie Huaisang might just be going along with Wei Wuxian's attempt to find secrets, but he's feeling paranoid enough that it's coming across as suspicious too.  

Time to go read some books.

Lan Wangji leads the three of them to the Cloud Recesses library. It's a truly gorgeous space: tall elegant shelves and plenty of light. Definitely lots of books.

Most of these books burned. All of the art, the hangings.

Wangji sits at his favored table in the center of the room and looks intently down at the first book he sees there, resolutely ignoring the other boys. He sits with his back straight, marveling at the absence of pain.

He has a lot to consider. Any books here about theoretical time travel, Wangji would know. Time travel might be mentioned within books that contain many different topics, but Wangji also knows all the important books of varied topics.

If the information exists, it will be in the forbidden section. He must figure out how to check.

In the mean time, he needs to decide what to do with Wei Ying, Wen Chao, the Yin Iron, all of it. He needs to figure out how to fix everything before it happens. There is so very much to fix.

"There sure are a lot of books here," he whispers, mostly to himself.  Probably none of them have pictures other than possibly technical diagrams.  Not that he really intends to read any.  

He'll stay close to Wei-xiong for the moment, though he intends to have a thorough walk through the room when he has the chance.

He's going to lean against a shelf and watch the other three to see what they're doing.  

Well, Wei Wuxian is making a valiant attempt to be interested in this library.

It’s such a boring library. At least half of the books in here are rules, and philosophical reflections on those rules, and treatises on the consequences of violating those rules, all of which seems utterly useless. Wei Wuxian is not finding any books about cool and spy-worthy secret magics. This is extremely disappointing. There might be any interesting information buried here if he searched long enough, but that doesn’t seem like the best use of his time at all.

It takes exactly three minutes for him to give up on being a library detective. He redirects his attention towards what is obviously the most valuable source of information here and plops down beside Lan Zhan to pester him.

oh no

“Hey! Hey, Wangji-xiong, psst. Wangji-xiong this library is extremely boring and my poor head is so tired already, can’t you just tell us where the interesting things are? Here, listen, Nie-xiong and Jiang Cheng and I think that the Wens are up to something, trying to find something here in Cloud Recesses. Don’t you think that’s likely? I mean, the Wen Clan has never attended one of the lectures of the Lan, so why are they here now? None of us know any secrets here yet so you have to at least give us a hint about what they might be looking for. What do you think? What’s in the Cloud Recesses that the Wens might want to find out about?”

“No idea.”

He doesn’t yet know what he’s going to do about the Yin Iron shard, but it definitely won’t involve putting Wei Ying anywhere near it.

“Ai, Lan Wangji you have to at least think about it. Maybe it’s something you’ve heard your uncle or brother mention - you don’t have any ideas at all??”

“None.”

He pouts, Loudly. “Wangji-xiong, what sort of spirit is that! Everyone says you’re the most perfect student and scholar of our generation, but here you are not even bothering to consider my question for even a minute, before giving up and deciding to live your life in ignorance? Aiyah, how disappointing. Don’t you want to try even a little harder?”

Maybe if he stares down at his desk intently enough he will cease to exist.

“How can you just ignore me in the middle of our investigation like this! Ji-xiong.

Lan Wangjiiiiii.”