This review may contain spoilers
Good idea, but not well executed
The series had really good potential with an interesting plot, but the ending was poorly done.The beginning was good, but then it started going downhill. It went from “we are solving a case” to “aliens”! It was as if the writer suddenly remember that the drama only was meant to be six episodes long and they needed to find a quick ending. So it became aliens and a cult? But what makes it worse is that it was the school teacher... Like what!
I think that if the drama had been longer, it could have built up a better plot twist and come up with a better ending. But all in all I wouldn't recommend it.
It's a waste of time.
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Tenía potencial...
La idea central de la historia tenía mucho potencia pero fue mal ejecutada. A medida que avanza la historia se empieza a ramificar en un montón de historias que al final quedan inconclusas. La persona que escribio está serie no tenía claro hacia donde quería ir y al final no fue a ningún lado. Está es una historia que tenía un gran potencial pero fue desperdiciado. Al final se me hizo aburrida y sin sentido. Además ninguno de los personajes logra crear una buena conección con uno como espectador lo que la hace una serie tediosa de ver.Was this review helpful to you?
Not as bad as everyone says
First of all - people need to understand what kind of story is the original webtoon. I found information about it - and it's some kind of anthology of short stories with one main theme - red lines above people's heads. No explanation how and why those lines appeared and why suddenly disappeared at the end of the webtoon. Just small personal stories of people whose life's become tragic and violent because of those lines. So, creators of this series tried to make one main storyline through the whole series and small personal stories of different people for each episode, except probably final.And the first five episodes worked very well with this concept. Story is interesting, acting is good, although I don't understand why Lee Eun Saem considered as main cast, because 90% of her screen time is in the first two episodes. But nevertheless, for the first 5 episodes everything is fine( but you can see the main twist with one character very early).
But the final episode...I don't think it's bad, but it's completely different from the rest of the series. It's very psychedelic, and the mystic part of the series starts working on 200%. And the ending...too many questions left unanswered, and this some kind of open ending (without season 2) could've worked(barely), especially as prequel to original webtoon, but the final minute of the last episode makes it impossible.
And here's my point and why I rate this series with 7, despite strange ending - I really hope for season 2. You can't end series like this. Friendly Rivalry has open ending - it's bad, with many questions, but it works as series final. Ending of S-Line doesn't work. So I really hope for season 2 with some answers ( and preferrably good answers, because webtoon doesn't have them). But if this is really the end of the series, then the exact moment I'll hear the news about it, I'll return here and change the rating from 7 to 5.
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absolutely pointless
there was no point to the story and the direction of the plot made close to no sense. why is anything happening and why does anyone gaf about who slept with whom. the cult-ish ending was meh. potential for a good plot but wasted. can lee soo hyuk change his agent? hes such a good actor this is a waste. there was a rape plot line that added nothing to the story overall too. a whole lot happening here but it leads to nil.Was this review helpful to you?
This review may contain spoilers
They build up the plot line so good, intriguing, with right amount of mystery, thrill and suspense but then gave it a disappointing ending like that like WHY WOULD YOU DO THAT!? It started off good, continued like so till ep 4-5 and then just straight up gave us some alien and paranormal showdown, without a good explanation or anything of sorts. It was SO MAJORLY DISAPPOINTING.
The moment I watched the first 2 eps, I knew either it's going to have an amazing ending, or it'll be majorly disappointing and nothing in between, guess it was the second unfortunately.
I'm only giving 6 because my favorite actor's there and he played his part well, well, till the 6th ep at least and because of the story build up. Trying it out and watching it can be a good experience, but I won't rewatch probably.
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Curiousity
The story is about a woman who can see red line that is quite mysterious. That red line is actually a connection to that person, whether they are having a secret or sex with someone. Later on, there is a person who gives a strange person a glasses that can see the red line. It makes the person like having a superpower and turns out to be an evil person...Was this review helpful to you?
A Promising Drama Ruined by a Disastrous Finale
What did I just watch? Honestly, I went into this show thinking it was underrated. The first few episodes had me intrigued. The unique premise had a lot of potential, and the build-up was pretty solid. But then… episode 6 happened. It felt like a completely different show. The tone shifted so drastically, it was almost as if the writing team changed mid-season. The pacing was all over the place, and the character arcs felt rushed and forced. I mean, the acting wasn’t bad, but it was like the actors were just as confused as the viewers.It’s honestly disappointing. The show had a lot of heart, and the first 5 episodes were solid. If they’d kept that same vibe and quality, this could’ve been something really special. But then the last episode came, and it all fell apart. The genre shift was jarring, the plot felt contrived, and it just ended up being frustrating. It’s a shame because this had so much promise, but that finale really tanked it. It’s hard to ignore how much the last episode just ruined the whole experience. Wouldn’t recommend it, honestly.
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Diminished Potential
I don't usually write reviews, in fact this is my first one, but this drama left me in such shock that even a day later I feel the need to write about it.Now, amazing story concept, good acting, interesting plot until...WHAT was that ending?? Where did it come from? This truly felt like the writers realized they had to wrap things up soon but didn't know how to, so they picked the unrelated fantasy option where they don't have to explain anything anymore. The sudden reality shifts, cultist sacrifices, and power hungry god were all introduced in the LAST EPISODE without any hints to it before then??
I had a lot of hope for the show and it really hooked me, especially when we found out the teacher was the one distributing the glasses, but all of that potential crashed and burned in that last episode.
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Incredible idea, wasted potential, Overhyped and Underwhelming.
I was all in for S‑Line seeing red strings of past sexual encounters felt wild, fresh, and exactly the kind of premise that could change the game. The visuals of the red lines crawling over his head were instantly iconic, became an instant meme paranoia at its best. and the show’s atmosphere and music were top‑tier. But after a strong start, the story quickly unraveled. What could have been a razor‑sharp thriller about shame, secrets, and surveillance became a messy mix of supernatural twists, rushed subplots, and a finale that abandoned its own serial‑killer tension for an odd dystopian turn. I really didn’t like the ending it felt dystopian and weird, but not in a good way, leaving me more frustrated than shocked. The characters, while intriguing especially Arin’s haunting performance and Lee Eun‑Saem’s unpredictable arc never got the depth they deserved, and by the last episodes the red‑line concept had lost its symbolic bite, reduced to a flashy gimmick instead of a meaningful commentary. It’s a show worth watching once for the cast and visuals, but in the end, the hype far outweighed the substance. Not unwatchable, but definitely overhyped. With the themes it tried to tackle, this could have been powerful instead, it ended up just… fine.Was this review helpful to you?
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Open letter to the production team
📢 Open Letter to the S Line TeamDear S Line Writers, Producers, and Wavve Team,
First of all, I want to say thank you for creating S Line. The concept was fresh, bold, and unlike anything we’ve seen in a K‑drama before. The red line idea was fascinating and had so much potential — it made me and so many other fans excited to tune in every week.
But as much as we loved the idea, we also need to be honest: the execution left us disappointed.
The last two episodes felt rushed and disconnected from the first four. The story suddenly shifted into confusing supernatural elements, and big moments — like Jun‑seon’s sudden death — felt unnecessary and poorly handled. It wasn’t just the fact that he died, but how his death was treated. There was almost no time for grief, no space for the weight of that loss, and it made the story feel hollow instead of heartbreaking.
Here’s what fans are asking for if there is a Season 2 (and we hope there is one!):
✅ Answer the questions you raised. Don’t leave the mysteries hanging with no explanation.
✅ Stop using unnecessary, out‑of‑nowhere deaths just for shock value. If a character dies, make it matter — and show real grief.
✅ Respect the emotional core of the story. Hyuno and Jun‑seon’s connection felt like soulmates. If you’re going to break hearts, do it in a way that feels earned.
✅ Stick to the concept you started with. The red line premise was enough. You don’t need random multiverse twists and unexplained supernatural moments to make it interesting.
We’re not saying this out of hate — we’re saying it because we care. We believed in S Line’s potential, and we still do. That’s why we’re asking you to listen to your fans and make Season 2 (and any future episodes) the best version of this drama it can be.
Sincerely,
A very frustrated but hopeful fan
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Intriguing but lost
Started the drama like everyone else to see the case live up to their potential. The drama was way too short. Story line missed around 50 pages in between. The first 2 episodes were slow and good and to be honest we were curious and rushed to watch the rest. They didn't elaborate with the concept of revealing in the next season maybe? I mean you can't end a drama with literally no context.. because the ending was definitely not a cliffhanger.I have no words for the acting because there literally was nothing to see. So, if you just want to start this drama out of curiosity from reels, you can... but omy ill you be disappointed.
This is just an honest opinion from a Kdrama buff, no allegations :)
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This review may contain spoilers
Was I anticipating every Friday for no reason?
The first 4 episodes really had me intrigued, to see how the plots will unravel, and oh was I disappointed. Do not get me wrong, the casting was good, the acting impressed me as well - but what were those plots?! If you have not watched yet and planning to, get prepared to be confused!I agree with many reviews that it was rushed. Everything was just thrown at me all at once (spoilers ahead), especially at the end where everyone was around the homeroom teacher and Hyeonhop. I really thought I wasn’t paying attention because what even was that?
The death I found so unnecessary was Hyeonhop’s boyfriend. I thought maybe their trope could be on the sideline, away from the main plot, but I was wrong. Yeah, there was mystery laced throughout the episodes, but I wish they delved into situations more rather than leaving it mid-catastrophe then moving on to another. Would I watch if there is another season? Yes, only because I’d like to see how they can continue the storyline after that ending, but I’ll watch it without getting my hopes up.
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