S LINES ❘ Lee Soo-hyuk, Lee Da-hee, and Arin

 S LINES (Korean title: S라인)  is dark fantasy thriller series starring Lee Soo-hyuk, Lee Da-hee, and Arin (of Oh My Girl), it is about a girl who is seeing red lines above everyone's head and realizes the meaning of those red lines not until she's high school.

Adapted from the webtoon of the same name by Ggomabi, it was written and directed by Ahn Ju-young.

Glowing red lines appear above people's heads, connecting anyone who has been in an intimate relationship — these are the "S Lines." Private secrets become public, and society is thrown into chaos. A detective, a mysterious teacher, and a girl born with the ability to see the lines get pulled into a string of strange deaths and conspiracies when special glasses that reveal the S Lines begin circullating.

Her power is to see a person's red lines, a string-like line, floating on top of the person's head is their number of times they had sex and if the line connects to another person mean that he/she had sex with that person. She is invincible even if she jump from a high place.

But there is a clear eye glasses if worn by a person they will be able to see the S lines too.

Premiere: July 11, 2025 (Wavve, South Korea)

Genre: Fantasy, psychological thriller, mystery

Production: Sidus Pictures

Main Cast:

- Lee Soo-hyuk as Han Ji-wook

                    Detective investigating the S Line deaths; when he puts on the 

                    special glasses, he sees dozens of red lines over his own head

- Lee Da-hee as Lee Gyu-jin

                    Mysterious high school teacher; calm, secretive, and has zero 

                    red lines — making her even more suspicious

- Arin (Oh My Girl) as Shin Hyun-heup

                    High school student born able to see the S Lines; lives in

                    isolation because of what she sees