While watching the first episode I thought that the disabled brother witnessed a murder and the butterfly is the symbol of his fear and something that the killer used or wore. After watching the second episode my theory was confirmed in parts. Because the butterfly symbols are pretty strong in this drama, I wonder if they are all connected. We Know that the amazing Leads have a common history. Also, we know from the start the fl was abused in several ways. I wonder if her mother used butterflies as symbol to hurt her and is involved in the killing of his mom for some inspiration for her books. What do you think? Which theories do you have so far? I’m curious for your thoughts! :)

Oh! I definitely like the idea that the FL's mother killed the ML's mother for inspiration. I too was thinking that the killer was wearing something in the shape of a butterfly, or even had a tattoo. I wouldn't be surprised if the two families were connected by this murder. As for my theory, maybe the ML's mother found out about the abuse (maybe she worked for the family, as they seemed like they were well off, given the fancy castle-like structure we see her in during the first episode), and so either the mother or father killed her. Maybe even unintentionally!

Yes, by episode 2 it had me thinking more so than episode 1. I am thinking more along the lines of the brother may have witness something that had something to do with the mother that he ended up associating with butterflies as well. Maybe not as far as the mother killing the ML's mother but maybe found her but didn't call for help...? Also I took note that the young version of Moon-Young was ripping butterflies in half during her "spare time" lol. That's another indicator that butterflies isn't a pleasant experience for her either. 

IT is a mystery for sure , I think the same the brother has something to do with it that why he dreams like this, I also think that the characters are aware of the past events to. They just reveal everything slowly and also it the way he said the cold ? eyes ? he seen them before. Like he remembers. Like she been though pain he understands and had experience of with same story as the tale at start must been them both. All I see so far. ?

Well, I must say the two protagonists which are Kang Tae and Moon Young know each other. We received some small hint from the script writes at the end of episode 1. Kang Tae said her eyes resemble the eyes of a person which he likes in the past and we see the retrospection of two kids, a boy and a girl who play each other and spend some time together. I think it is Kang Tae and Moon Young when they were young, they just don't figure it out yet.
When it comes to Mong Tae Hyung  I am pretty sure he saw something, something which is connected to death and butterflies. Maybe he saw the culprit of a crime, and he was cashing to kill him. I haven't seen the second episode yet, but I have a strong feeling something is fishy here!
So far, so good! I already love this drama!

I don't know if anyone noticed, but in the first episode remember the man that was about to dubble suicide with his daughter was found dead that very same day. Remember the mc went back to do something. She left an autograph for the kid but just maybe she killed the dad... Do you  guys maybe think that mc represents the butterfly and maybe is a murderer?

Well,  I think that would be a contrast to the healing story. When she committed homicide It’s hard to save her character without punishment and an Happy End. It’s a wrong hint imo.

I don’t believe it was her, I am sure they made it seem that way but I choose to believe she only went in there to leave the signed book for the little girl. Even she said it herself in the scene when Gang-Tae stopped her that she was going to give him a little cut but he went overboard and hurt himself. We know she doesn’t give a damn what anyone thinks of her so there was no reason for her to lie about her true intentions.

Butterflies are a symbol of dissociation, multiple personalities, mind control and hypnosis. Butterflies are used extensively in popular media as symbols of these things.  One clear example that comes to mind is Katy Perry's "Wide Awake" music video.  I believe it originated in eastern religions, but it has come to be widely recognized as a symbol of the CIA's trauma based mind control program called Project Monarch.  It suggests that the characters in this story have mental problems or breakdowns due to severe childhood trauma and mental conditioning. 

It's also a hint to the viewer that "what you see isn't reality."  A good example of this is in one of the last scenes of the drama "Extraordinary You". A butterfly lands on the heroine and she smiles at it, suggesting that the whole happy ending we witnessed might just be in her head. 

Nice conclusion! :)

I want to add the known symbolism of butterflies in general. Butterflies are deep and powerful representations of life. Many cultures associate the butterfly with our souls. The Christian religion sees the butterfly as a symbol of resurrection. Around the world, people view the butterfly as representing endurance, change, hope, and life. There is no doubt the butterfly has significant meanings to us.

Through heartfelt stories, we have heard butterflies symbolizing the passing of a loved one, or life struggles that people have endured to emerge as a better person. We have heard stories from cancer fighters and survivors, people who have dealt with mental breakdowns, heartache, and drug addictions. Butterflies have also been a symbol for celebrations, weddings, life, and our journeys.

In mystery japanese manga i read, butterfly usually symbolize as missing soul and tragedy. By looking the brother see happy think in colorful way, and dreaming buttefly in dark tones, maybe he seen her mother killer while he was hiding in some dark place. I suspect maybe FL mother have a butterfly collection in her room. With father like that, and mother who being detective & murder writer, and also her words in the beginning of Episode, gives clues that her mother is not 'a normal' mother. I can't wait who will this mother will show later in this drama. 

I also think one of here parents is the culprit. Also remember how her father tried to strangle her ? Meaning he is capable of killing someone. And there was this scene where she was killing butterflies. It makes me think that she hates butterflies for a specific reason that might be related to one of her parents or both as we already know they were both abusive towards her somehow. 

Here are a lot of theories I am really curious what will be next.  Moon Sang Tae acting is so perfect facial expression his voice this makes look so real. And also I’ve been waiting for the main cast Come-back.  I also believe that butterflies here will be a common thing that brings them together “ Those damn nabi “

Can’t wait for episode 3 it’s Thursday midday and I can’t wait anymore 

I believe that the butterfly reference in the "butterfly hug"  represents resurrection and new life.  After you wrap yourself in a "cocoon" embrace, you are calmed and emerge with a "new life" no longer controlled by your mental disorder in a triggered event.

Moon Young tears wings off butterflies in what appears to be a way for her to release her anger by torturing them.   Sang Tae is terrified by butterflies flying after him and he connects it with his mother's murder.  I do not know what the butterflies represent in these situations or if there is any connection, but it is something to look forward to discovering as the story unfolds.

Moon Young is tortured by her anger and tortures butterflies. (could have another reason)

Sang Tae is terrified and haunted by butterflies.

Kang Tae uses a "butterfly hug" to help heal others.

Oh my world it’s so interesting and very hard to wait for what is next. This year for korean drama will be the best! A lot of drama has been realized and is waiting other dramas ahead! It’s okay not to be okay is the best drama to open the second half of the year.