This review may contain spoilers
"CONTAINS SPOILER" Started off incredible, ended in nonsense. Complete waste of potential
I started watching S Line thinking it was going to be a high-concept thriller about society’s obsession with secrets and sex. And for the first 5 episodes? It was. But then Episode 6 happened... and I’m still trying to process how we went from a sharp, disturbing social experiment to this metaphysical fever dream.
The show introduces us to Arin (Sin Hyeon Hop), a girl cursed from birth with the ability to see “S Lines”—bright red glowing cords linking people who’ve had sexual contact. It isolates her, traumatizes her, and builds this quiet horror around knowledge she never asked to have. Then come the glasses. Now everyone can see what she sees. And all hell breaks loose.
We follow cases of betrayal, guilt, and spiralling madness—spouses turning on each other, students breaking down, adults consumed by paranoia. Each episode feels like a short film: intense, tight, and thematically loaded. Detective Ji-Uk (Lee Soo Hyuk) acts as a grounding force at first, trying to connect the dots behind the glasses’ appearance and protect those affected. Their dynamic—Arin’s cursed detachment vs. Ji-Uk’s human empathy—is one of the strongest parts of the show.
But from the start, Ji-Uk had hundreds of red lines above his head, and the show never gives us a satisfying answer about them. Is it trauma? Was he a victim? Is he the key to the S-Line curse? We don’t know. Instead of addressing it, the story goes off the rails in the final episode.
In Ep 6, we suddenly shift into an alternate world, with Gyu-Jin (the eerie, omnipresent girl) practically turning into some godlike creator figure, deciding the world must "see the truth" through her crimson-tinted lens. She spreads the vision globally, turning her curse into humanity’s shared burden. Now everyone wears visors, helmets, and glasses to avoid seeing the red lines—essentially becoming what Arin was all her life: hidden, afraid, numb.
Ji-Uk’s arc, too, shatters here. He uncovers that his own father sexually abused the niece he’s been raising—an utterly horrifying reveal. But the emotional fallout gets shoved aside for a visually cool but narratively weak confrontation on a rooftop, where time and space collapse and Arin and Ji-Uk walk through multiple realities. Why? No real answer. Gyu-Jin turns almost mythic, but without any actual character development, it just feels… empty. Almost like the writers ran out of time or budget and decided vibes > logic.
What frustrates me most is the wasted potential.
They had everything—visual symbolism, moral ambiguity, layered characters—but chose spectacle over resolution. What was the origin of the glasses? Why did Arin’s mother kill herself? Why did Ji-Uk have so many lines? WHO EVEN IS GYU-JIN?!?
Verdict:
Watch it for the performances and the premise. But lower your expectations for closure. It’s brilliant until it’s baffling. And if Season 2 never comes, I’m just going to pretend Episode 5 was the finale.
The show introduces us to Arin (Sin Hyeon Hop), a girl cursed from birth with the ability to see “S Lines”—bright red glowing cords linking people who’ve had sexual contact. It isolates her, traumatizes her, and builds this quiet horror around knowledge she never asked to have. Then come the glasses. Now everyone can see what she sees. And all hell breaks loose.
We follow cases of betrayal, guilt, and spiralling madness—spouses turning on each other, students breaking down, adults consumed by paranoia. Each episode feels like a short film: intense, tight, and thematically loaded. Detective Ji-Uk (Lee Soo Hyuk) acts as a grounding force at first, trying to connect the dots behind the glasses’ appearance and protect those affected. Their dynamic—Arin’s cursed detachment vs. Ji-Uk’s human empathy—is one of the strongest parts of the show.
But from the start, Ji-Uk had hundreds of red lines above his head, and the show never gives us a satisfying answer about them. Is it trauma? Was he a victim? Is he the key to the S-Line curse? We don’t know. Instead of addressing it, the story goes off the rails in the final episode.
In Ep 6, we suddenly shift into an alternate world, with Gyu-Jin (the eerie, omnipresent girl) practically turning into some godlike creator figure, deciding the world must "see the truth" through her crimson-tinted lens. She spreads the vision globally, turning her curse into humanity’s shared burden. Now everyone wears visors, helmets, and glasses to avoid seeing the red lines—essentially becoming what Arin was all her life: hidden, afraid, numb.
Ji-Uk’s arc, too, shatters here. He uncovers that his own father sexually abused the niece he’s been raising—an utterly horrifying reveal. But the emotional fallout gets shoved aside for a visually cool but narratively weak confrontation on a rooftop, where time and space collapse and Arin and Ji-Uk walk through multiple realities. Why? No real answer. Gyu-Jin turns almost mythic, but without any actual character development, it just feels… empty. Almost like the writers ran out of time or budget and decided vibes > logic.
What frustrates me most is the wasted potential.
They had everything—visual symbolism, moral ambiguity, layered characters—but chose spectacle over resolution. What was the origin of the glasses? Why did Arin’s mother kill herself? Why did Ji-Uk have so many lines? WHO EVEN IS GYU-JIN?!?
Verdict:
Watch it for the performances and the premise. But lower your expectations for closure. It’s brilliant until it’s baffling. And if Season 2 never comes, I’m just going to pretend Episode 5 was the finale.
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