How do u guys think the romance will start between them?.. Give ur predictions..

For me, I feel like she will see find out he is the intruder, and will question him about his purpose, though i don't think he will tell her his true identity..I feel like maybe she will accidentially see him mysteriously going somewhere like the NIS office & follow him..idk what i 'm really saying here..

you all tell me ur opinions...

Yes, i completely see ur point here...

I also feel like though maybe romance may start to blossom at the skl between them but the theory of if his actual identity get revealed will have a different tang to it...

Let wait and see...

 Stargazing:

As per FL, current ML is look alike of her first love. Let's see what did this current ML did in his past to hurt her or any chances ...current ML's twin brother was actually FL first love.

If this ML is indeed the first love then chances are there to see their past romance as flashback as well as new romance in the school. I think This time it will be ML to take initiate in the relationship.

Once ML 's true identity get reveal , I will write my theory on that.

Umm I think you are talking about some other drama. This has nothing of the sort 😂

Omg,i was also about to say this too...cause i really didn't understand what's they were suddenly talking bout...

No, u misunderstood smth..it said the fl saw her first love in him, this could mean that maybe just like how our heart flutters when we start to like someone for the first time ( romantically), the fl type was reminded of her first love by looking at him....or if they were to do it like this he may actually be her first love maybe when they were young..(u know how kdramas do their things)..

Do u get it???

From Soompi: "Soo Ah works at the prestigious Byeongmun High School, where she is known for her strong principles and deep care for her students. However, Oh Soo Ah notices a striking resemblance between Jung Hae Sung, a new student in her class, and her childhood first love who deeply hurt her. This triggers a series of dramatic events in her school life." Considering this is a K-drama, the ML is definitely going to turn out to be her childhoold love, kdramas love their childhood connections. 

This article seals the deal of them having a childhood connection : https://www.soompi.com/article/1724245wpp/jin-ki-joo-is-an-optimistic-teacher-with-a-hidden-past-with-seo-kang-jun-in-undercover-high-school

"Adding to the intrigue, Soo Ah and Hae Seong share a hidden past that gradually unravels as the story progresses. Who will recognize the other first? What untold history connects them?"

 Illustracat:

From Soompi: "Soo Ah works at the prestigious Byeongmun High School, where she is known for her strong principles and deep care for her students. However, Oh Soo Ah notices a striking resemblance between Jung Hae Sung, a new student in her class, and her childhood first love who deeply hurt her. This triggers a series of dramatic events in her school life." Considering this is a K-drama, the ML is definitely going to turn out to be her childhoold love, kdramas love their childhood connections. 

I knew they will  somehow have that  childhood connection in this drama...what resemblance of first love lol...he is obviously gonna be the first love, just that they can't remember,that's just it.. 

I don't think there's any twin, that's too makjang for this type of drama. Also resembling can mean similarities in behaviour not just looks. "Who will recognise the other first?" This sentence clearly indicates they knew each other. 

We are actually up to smth here, but let's see what our dear drama goes by it...

I don't believe in a twin brother either. Soo Ah and Hae Seong  met when they were younger (First love). Hae Seong changed his name because he was bullied and dropped out of school so they didn't meet each other until now. But of course they don't remember each other after so many years apart.
I believe Soo Ah somewhere in episode 5-7 finds out that Hae Seong is undercover and together they investigate both the evil principal and all the ghost stories etc. In that way they come closer to each other for each day and feelings rise between them and then they finally figure out that they know each other from the past. But then Soo Ah remembers that she was hurt by him (don't know how) and they have an argument. Hmmm...well the rest...I will tell you later. :)) LOL

 Illustracat:

This article seals the deal of them having a childhood connection : https://www.soompi.com/article/1724245wpp/jin-ki-joo-is-an-optimistic-teacher-with-a-hidden-past-with-seo-kang-jun-in-undercover-high-school

"Adding to the intrigue, Soo Ah and Hae Seong share a hidden past that gradually unravels as the story progresses. Who will recognize the other first? What untold history connects them?"

This feels like a spoiler. Why does Soompi need to give extra details which have not appeared in the drama yet.