The first plotline that got focused on through out the series is the conflict between the two homeroom teachers Jung In-jae and Kang Se-chan who look at their jobs very differently. Jung looks at her job as a way of preparing all the kids for the world and she believes it is her personal responsibility to help the kids with any problems that they may be having whether it regards school work or not, she goes above and beyond what her job requires her to do so this leads her to sometimes focusing too much on getting everyone's attention rather than just teaching those who actually wants to learn. Kang who usually works as a tutor at night schools where only students who are very serious about attending university go to but is forced into a teaching position because of profiting off some sort private tutoring, the only thing that Kang cares about when it has to do with students are their grades. By being forced to work together Jung and Kang learn to understand the other's point of view and in the end Kang even ends up admiring Jung for the way she never gives up on the students even though he doesn't feel like he could ever allow himself to connect him the way that she does and Jung learns that sometimes no matter how hard you try you can't get through to every student.
The next plotlines of importance I would say would be the ones that involve Go Nam-soon who is a seemingly apathetic slacker who the wannabe gangster in the class Oh Jung-ho and his two friends harass on a seemingly daily bases and while Nam-soon never directly challenges him it's clear that he doesn't fear like the rest of the class but rather that he finds the idea fighting them to be too much of a bother to deal with. Things in the order of who the strongest in the class really starts to get confusing when Park Heung-soo transfers into the class since he seems to have a past of getting kicked out of school and fighting which makes the students other than Nam-soon think of him as dangerous and troublemaker despite the fact that all Heung-soo wants to do is go to school and graduate without causing any trouble. Nam-soon knows Heung-soo since the two of them are former friends and their friendship end with Nam-soon hurting Heung-soo and neither of them have completely gotten over how their friendship ended which causes all sorts of tension in their interactions with Nam-soon feeling so very guilty and wanting to do anything he can try and make up for the past even though he doesn't believe it's possible and Heung-soo being understandable still very anger at Nam-soon. Finding out about what destroy Nam-soon and Heung-soo's friendship and seeing them having to figure out if the can repair their friendship is both the most painful and rewarding part of the series.
The third kind of plot line that this series has are the ones that deals with the academic pressures that students either have placed on them or place on themselves. The top student in the class Song Ha-gyeong wants nothing more than to get into S University and she will do everything she can to get in their which leads her to taking classes illegally at tutoring schools and using some type drugs to stay awake for days when finals week come up so that she can stay up to study. Throughout the series Ha-gyeong ends up learning to not value school work over anything else once she ends up hurting her best friend over it and after that she accepts that there are other things that she cares about more than school. Another student in the class that deals with a lot of academic pressure is Kim Min-ki who's mother has basically planned out his whole life and pretty much micromanages ever aspect of it especially when it comes to studying. The pressure that Min-ki's mother puts on him is something that he ends up feeling so overwhelmed by that he almost kills himself and it's only after that he can get his mother to back off of him a little bit and allow him to have a few more choices about his future.
Overall I really loved this series I thought that it had a great cast of characters and I really enjoyed how this series was able to focus so much on friendships through it's run and I just loved seeing all those relationships develop along with the characters. This series was really great and recommend it to anyone who likes teen dramas because this is a really good one that is more grounded in reality than most. Please tell me your thoughts on this series.