What is so special about the S Line and the red thread in the movie that it has caused a global 'fever'?

Everyone has a secret. But what if your deepest secret was suddenly exposed by a red string hanging above your head, connecting you to every sexual partner you've ever had? Privacy would cease to exist.

The mystery-fantasy thriller S Line  will explore how people are connected, exposed, and judged by these red threads. Here are the highlights of the Korean film S Line that made it a global "fever".

S Line is a live-action adaptation of the popular provocative webtoon of the same name by Kkomabi. The film's director and screenwriter is Ahn Joo Young, known for works such as "A Boy in Sungreen", "Pig Riding Hood", "Cartwheel".

The film depicts a supernatural phenomenon where a red line (S-line) appears above each person's head. These lines connect them to everyone they have ever had sex with.

S Line has special content

The story follows Hyun Heup, a young girl born with the special ability to see indelible red lines hanging above other people's heads. These lines connect them to their love partners.

However, global chaos ensues when someone suddenly invents a special pair of glasses that can mimic her special ability, allowing anyone who wears them to see these " S-lines ". When everyone's private histories are suddenly exposed, society falls into chaos. She teams up with a detective to find out who is responsible for creating the glasses and selling them on the black market, ultimately stopping the growing problem.

The film explores the dire consequences of losing all privacy when people are suddenly connected, exposed, and judged for past relationships.

Impressive cast and characters in S Line

Arin (OH MY GIRL) as Hyun Heup

Hyun Heup is a high school girl who has been able to see the "S Line" all her life. Born with this special ability, she becomes the central figure of a mysterious case.

Lee Soo Hyuk as Han Ji Wook

Han Ji Wook is a free-spirited detective with an impressive appearance and mysterious aura. He is the detective in charge of investigating the "S Lines" case.

Lee Da Hee as Han Gyu Jin

Han Gyu Jin is a high school teacher with a bold and unusual personality. She is fascinated by the "S Line" phenomenon, and gets caught up in the mysteries surrounding it.

Why should you watch S Line movie?

Based on a popular webtoon

The drama is based on a webtoon by Kkomabi, the famous author who created the Netflix hit "A Killer Paradox."

Premiere at Cannes

Before hitting the small screen, "S Line" has attracted significant attention worldwide. The film was selected for the Main Competition at the 2025 CANNESERIES (Cannes International Film Festival), where it gave a first impression to global audiences.

Provocative and controversial topic

The S Line drama is based on a clever webtoon. The original story is famous for its social commentary. It explores themes of privacy, judgment, and relationships. The plot will expose the history of human sexuality.

The perfect blend of genres

S Line is a blend of science fiction, fantasy, mystery, social commentary and human drama. The film brings a lot of fun for all audiences.

Arin's return to the screen

Oh My Girl's Arin is back on the small screen with a new role. This time, you can witness Arin's acting progress as she takes on a more mature and complex role.

Impressive cast

The visuals of the cast in the drama are undeniable. Lee Da Hee's strong charisma, Lee Soo Hyuk's impressive appearance, and Arin's charming charm. Their visuals further reinforce the reason to watch their chemistry and interactions on screen.

The film raises topical issues.

Private lives are often made public in today's social media age. The themes the film explores, such as privacy, shame, and social judgment, are all hot topics right now.

Korean movie trailer S Line