What if your past relationships became visible in broad daylight, marked by a red line that everyone could see? This is the novel concept of S-Line, a new K-drama blending fantasy and suspense, starring Lee Soo-hyuk, Arin (Oh My Girl), and Lee Da-hee. Adapted from the popular webtoon by Kkomabi, this series explores the social consequences of a revealing… and potentially dangerous… supernatural phenomenon.
In S-Line, red lines appear above people who have had a physical relationship. This phenomenon disrupts social relationships, exposing secrets that some would prefer to keep buried.
The story follows a young woman who has been able to see these famous red lines for as long as she can remember. But her unique ability loses its exclusivity when special glasses offering the same vision begin circulating on the black market.
As these invisible connections become visible, a mysterious murder calls everything into question. What is truly hidden behind this supernatural phenomenon? What is the connection between these involuntary revelations and the crime committed? The series combines suspense, investigation, and emotional tension around these lines that expose the intimate.
The Cast of S-Line
Lee Soo-hyuk plays a detective who discovers the existence of S-Lines thanks to special glasses. His investigation marks the beginning of this spiral of revelations.
Arin, a member of Oh My Girl, plays a high school student who has been able to see these red lines since birth. She lives in seclusion, keeping her secret to herself.
Lee Da-hee plays a teacher whose lack of a red line raises questions: why does she have no visible connection with anyone?
The dynamics between the characters, especially Arin’s performance, bring real depth to the story.
The S-Line drama premiered on July 11, 2025. It consists of six episodes, airing two episodes each Friday.
S-Line has already distinguished itself by winning the Best Music Award at the 2025 Cannes International Series Festival. It is the first Korean series to receive this distinction. Critics praised the quality of the script, the performances of the actors, the art direction, and the immersive soundtrack. The series is co-written and directed by Joo Young-ahn.
