Let the speculations begin!

By the way i think the main villain in this story is the female doctor. The mayor is probably gonna turn bad soon, he seems like a greedy person with a hidden agenda.

Most of the comments points down as to why PCH is the big mouse. But I  want to point out things that prove he is not...

Some people say that PCH knowingly is conning everyone around him. But why I don't think so is then why should he fix the camera in the prayer hall? His main intention at that time was to figure out who actual BM is. Otherwise there is no need for him to do that and even suspect Jerry as BM. Also he constantly hates BM for making him suffer like this. Even at the end of ep 8 he says that he won't end up like Jerry.

One of the users also pointed out how the flashback scene was actually PCH conning yoona and others to buy expensive milk... That was interesting at first read but I don't think that's true. In my opinion, the main purpose of that scene was to focus on the orphanage that certainly seems as the main thing behind all this. BM might be related to that orphanage and might know PCH from the beginning and thus chose him as his tool.

Now, if we see the DID theory, that again seems weird. And I totally think this is definitely wrong bcaz of that dream scene. I think the writers purposely kept that scene in order to make us fool in believing the DID theory.

Jerry is also not BM because when PCH questioned him he was so disappointed after knowing that PCH is not BM. Also he drugged PCH as his sister accepted money from GJH. If we really was BM then drugging PCH was unnecessary. Also he knew BM only after getting released from jail as he said he got money from BM and helped PCH escape.

My main suspect of BM is Ju hee... Bcaz it is suspicious that she didn't dismiss mi ho even after knowing that she is PCH wife and trying to find SJY paper. Yes she told her to retire voluntarily but did not take any action towards it when she refused and when she even sneaked into the restricted area. Also when the elder asked her to carry on his position, she refused.
Also many of the inmates in prison died bcaz of cyanide poisoning which would be easily accessible for a hospital director. One more reason is initially when the prison mates visualise about who the BM is, various theories scene came on, one of which was that BM is actually a lady. This might've been a small clue I guess but not sure.

One more person whom I suspect is PCH's father in law. Bcaz all the gold and money was found in PCH's office which he had access to. Also PCH just mentioned budol mountain randomly when GJH tortured him. But there was actually gold there. Since it was the love spot of PCH and miho, I think PCH FIL might've known this place. And Jerry said to PCH that he got money from BM and in previous scene he gets money from mi ho and her dad. I also think that's when Jerry realised who real BM is.

 Isabelle:

random suspicion, but what if big mouse is his wife

Not so random. I think it might be her too. She's one of the very few people who knew he was trying to catch BM with this camera.

It's possible that she hided her money at her husband's workplace and that she was just as surprised as him when the police found it.

 Muhammad Ibrahim:

It's kinda weird why a hotshot Mafia boss would call himself big mouse, seems underwhelming; a mouse usually feed on leftovers of humans they are basically the lowest why would someone call himself that. I think that big mouse isn't someone specific, maybe it's a fictional character that various people borrowed it to do bad deeds without implicating themselves throwing the blame on big mouse, maybe some people in the prison used big mouse persona to do their bad deeds, maybe even the mayor used big mouse to rob lala capital, since they are basically enemies. 

As I suspected the mayor robbed lala capital and dumped the deed on big mouse. Alright it seems that Jerry is no working for big mouse or he could be big mouse himself. Those are my suspects for now 

This drama frustrates me in a good way, if it make sens. Like i'm still unsure, what will be the final conclusion

1. So everybody are sus for me lol. For sure,  what we all know/predicted, everybody gains something from the facility and overall this whole Mouse mess.  But i'm really conflicted about  Park Yoon Gab. I mean..i have impression, that some people. try to outsmart the game if it make sens?  Same is with Jerry.  It's like some witch hunt(h)ing for the Mouse. And i think most of the people bluff, or they indeed had some instruction, but maybe the fake one? It really bothers me for example this scene in hospital,  with Jerry.  What was the reason, to swap the message? To make them antagonistic to each other?  If he was the  Mouse, he should predict it imo and also wouldn't be so mad. OR it was a stunt? 

2.  This whole illness mess. I wonder  - it looks like Hyun Joo Hee  made there some experiment ground, and  higher up's are more less aware of some parts of it.  It's imo interesting tho, they pick the most "good"  prisoners. They want the most obedient one?  They once proved, they will do anything, for some profit, so they will go with the instructions from med staff, and will take anything?  And in context of that - started to wonder if "Mouse" wasn't their first "test", and now he wants revenge?  Also if we still belive, that tattoo indicates wider group - maybe we have more people, who were tested there? 

3. This tarot crap - yeah,  No Bak seems to be the obv one. Still - i wonder, what with his daughter? 

But again, maybe it's misleading.  Imo tarot itself is some kind of clue. Because it's not only to know/learn about it, but also understand the context of it, in the present time. Like, it's not some metaphorical prediction,  in this case it's literal message about what will happend or will happen. Also i wonder- does Chang Ho  missed some cards? More people founded them, and use as a clue for something?  But imo indeed is's sound like some test.

4. And the  big Elder stuff. So it will be a random thought on it 

• It seems like this guy doesn't like his son-in-law for sure, to put it mildly. We know, that business, mostly will go, to the men hands, so i belive he's very disapointed on  Joo Hee   choice, if it's about her husband 
• So i started to wonder, if he will not try to find alternative succesor for, whatever he has. And now - or indeed Park Chang Ho  will be some lost grandson or other crap, and still Oldie wants to test him  OR  he picked him from other reason to test 
• Connected to theory 1, what if the real Mouse is somehow related to the Old Man?  but maybe he hates his family for whatever reason, and using main hero, he want crash  his grandfather? or simple wants to test his family intentions and still test his family/take some revenge on them 
• What if real Mouse, use Park Chang Ho , to hide and play some dirrty game with  his grandfather?

Anyway - too much imposters lol, still i think we have some bigger plan, and some of the people maybe gain from it, accidently, And as for the real MOUSE - Park Chang Ho , Choi Do Ha , No Bak , Old Guy or simple bunch of people, who will bambozlee as in the end? :P 

 Milisia:

This drama frustrates me in a good way, if it make sens. Like i'm still unsure, what will be the final conclusion

Yeah. The writer is so good in leading the audience in different directions and then revealing something else altogether.

Oooh good analysis!

I love that!

 Milisia:

Anyway, it would be very funny, if at the end, it it would turn out that it was all a bluff.. That paper is fake/non-existing, all of them are fakes/rumours etc. And Mouse was simple an "accident" which they ain't able to copy anymore.

haha. I hope not. That's like after watching a show, or after finishing a novel, it was all a dream. LOLs.

But yeah, there is some fine thread leading down that path. They're all obsessed about the research but all it says is the experiment is impossible. ^_^;;

I think professor sea medical paper is about some sort of drug that make whoever uses it become addicted and if he stopped it, withdrawal side effects will be trigger so they do everything to get more which means more money to whoever sells it. Those side effects as seen before hallucinations , shivers and blood vomiting, anyways they pick the role model prisoners because they are the only ones working and paying money for the so called vitamins that they give to prisons, the problem is that usually drugs or narcotics leave traces in blood which could be easily detected by authorities, so my guess is that professor sao papers is about drugs that don't leave traces, but for sake of trials they need some genuine pigs to test those drugs which is basically the prison...