How Lee Soo Hyuk's S Line went from a steamy K-drama to internet’s red-thread obsession — now linking way more than just lovers

If you’ve been scrolling through Instagram lately and noticed glowing red lines floating above people’s heads, sometimes even connecting them to others, you’re not alone. These mysterious visuals are inspired by the new K-dramaS Line, starring Lee Soo Hyuk ofDoom at Your ServiceandTomorrowfame. The show’s influence has sparked a full-blown trend, spreading across TikTok, Instagram, and even X.

Curious what those mysterious lines actually mean? We’ve got you. Keep reading to find out what the red lines symbolise and check out some of the funniest S Line memes lighting up the internet right now.


The trend blowing up across social media traces back to the Korean thriller S Line, which started streaming on Wavve in July 2025. The show follows Lee Gyu Jin (Lee Da Hee), a woman who suddenly begins to see glowing red threads, called S Lines, connecting people who’ve had sexual relationships. Things take a wild turn when a mysterious pair of glasses is introduced, allowing others to see these lines too. In a society where discretion is everything, the fallout is immediate and intense.

A big part of the trend’s appeal lies in its layered symbolism. The red lines represent invisible sexual bonds, sparking conversations about privacy, shame, and societal pressure. At the same time, the plot keeps things gripping, as Gyu Jin teams up with Detective Han Ji Uk (Lee Soo Hyuk) to track down whoever is behind the glasses. The drama is based on Little Bee’s hit webtoon of the same name, which already had a loyal following—now amplified by the show’s moody visuals and bold premise.



While the show delivers a sharp commentary on privacy and relationships, it’s also become a full-blown meme online. If you haven’t jumped on the trend yet, don’t worry; we’re breaking down how people are putting their spin on it so you can join the bandwagon too.

And while S Line originally refers to sexual connections between people, the internet has taken creative liberty with it. Now, those glowing red threads are being used to show connections to just about anything: your favourite snack, a celebrity crush, a video game obsession. Basically, if you’re emotionally attached to it, there’s probably an S line.


What’s S Line without a touch of luxury? For many, it’s not just about people—it’s about what they can’t live without. Think ChatGPT, a black card, a sleek car, money, a favourite pillow, and yes, a partner too.

Her S Line smells expensive

One viral post takes the trend to fragrant new heights. Instead of linking to people, the red S lines coming out of her head connect to a glamorous lineup of high-end perfumes. It’s less about past flings and more about signature scents. With the caption “My kinda S-line 🎀,” she makes it clear that her strongest bonds are bottled, bougie, and smell divine.

S Line but make it delulu

Another fan-favourite take? A post that features a silhouette of a woman with red S lines linking her to an entire gallery of K-pop idols and Korean actors. With the caption “Na minha cabeça…” (which translates to “In my head…”), the meme turns the idea of S Line into the ultimate fangirl fantasy. From BTS members to K-drama heartthrobs like Cha Eun Woo and Park Seo Joon, the visuals turn her daydreams into digital reality. Because who says imaginary relationships can’t have glowing red threads too?

S Line, but it’s just stress

Not all S Lines are romantic—or even fun. Instead of connecting it to romantic pursuits or luxuries, several threads link to everyday stressors like job, exams, mental health, back pain, career, and 99+ other issues.


It’s a painfully relatable take that captures how the internet is using the S Line trend not just for aesthetics or fantasy, but also to poke fun at the overwhelming chaos of adult life. Turns out, the real S Lines are the burdens we carry daily.


The K-drama S Linehas become a cultural flashpoint since its premiere on July 11, 2025, on Wavve, with its provocative concept of glowing red “S Lines” that reveal past sexual connections. Lee Soo Hyuk’s character, Detective Han Ji Wook, has especially captured attention for the sheer number of lines emanating from his head in one standout scene.


The show began with episodes 1 and 2 on July 11, followed by episodes 3 and 4 on July 18, and will conclude with episodes 5 and 6 dropping on July 25, 2025. S Line made its international debut at the 8th Cannes International Series Festival, where it became the first Korean drama to win the Best Music award in the long-form category.

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