S Line

7.7
2025

Production

Logo for Sidus

A young woman with the ability to see mysterious red connections between lovers discovers her secret gift is no longer unique when special glasses granting similar powers appear on the black market.

Trailers & Videos

Thumbnail for video: BANDE-ANNONCE / S LINE - Compétition

BANDE-ANNONCE / S LINE - Compétition

Seasons

6 Episodes • Premiered 2025

Han Ji Wook is a detective looking to know what is the truth behind the mysterious red line. Kyu Jin, a funny high School teacher. Hyun Hob, a high schooler who has been able observe the red line from birth. The show will present the story of a cryptic red line that appears over head of the people in the show, connecting them to people with whom who have had sexual relations with them.

Still image for S Line season 1 episode 1: Girl With Sunglasses

1. Girl With Sunglasses

6.0

Hyun-heup, a girl who was born with the ability to see the S-line that indicates sexual relations. Because of this ability, Hyun-heup's family faces tragedy, and Hyun-heup becomes a reclusive loner for a long time. Then one day, a series of suspicious murders occur around Hyun-heup, and Hyun-heup uses his ability to see the S-line to track down the case...

Still image for S Line season 1 episode 2: Animal Kingdom

2. Animal Kingdom

6.0

Hyun-heup goes to Bangju High School after receiving a mysterious text message. There, he reunites with Seon-ah, a middle school classmate and Ji-wook's niece. However, Seon-ah is a victim of bullying from bullies. One day, when the bullying from bullies reaches its peak, Seon-ah discovers a mysterious pair of glasses in her locker...

Still image for S Line season 1 episode 3: Apartment

3. Apartment

6.5

Seon-ah falls from the rooftop and falls into a coma. Ji-wook cries out in self-reproach and anger, and cooperates with Hyun-heup to find the culprit. Meanwhile, Jung-woo, an English teacher at Bangju High School, witnesses his girlfriend's affair before their wedding and breaks off the engagement. And soon after, he finds a pair of glasses on his desk...

Still image for S Line season 1 episode 4: Meishin Hotel

4. Meishin Hotel

6.5

Ji-wook, who was continuing the investigation to find the culprit of the Seon-ah incident, hears about the S-line from Hyun-heup, but doesn't believe it. Meanwhile, Bang Ju-goo, an employee who lives in a goshiwon and dreams of becoming an actor, finds S-line glasses at Mi-seong's house and feels liberated, but soon after, he sees a woman connected to the music teacher he had a crush on and feels strong jealousy...

Still image for S Line season 1 episode 5: The Glasses

5. The Glasses

6.5

Ji -wook, who finally discovered glasses in the bloody bathtub of aesthetic, admits that the words of Hyun -suk were true. Use the power of glasses to start an investigation into sexual violence in the runway. And I think that the person connected to the only one S line of Sun -ah is the culprit of the Sun -a case.

Still image for S Line season 1 episode 6: S Line

6. S Line

5.5

Ji -wook finds out the truth about Sun -ah's S -line through glasses. Meanwhile, Hyun -suk, ahead of his 18 -year -old birthday, makes a big decision and meets the Jun -sun, which leads to an unknown confusion.

Cast

Photo of Lee Soo-hyuk

Lee Soo-hyuk

Han Ji-wook

Photo of Choi Ye-won

Choi Ye-won

Shin Hyeon-heup

Photo of Lee Da-hee

Lee Da-hee

Gyu-jin

Photo of Lee Eun-saem

Lee Eun-saem

Kang Seon-ah

Photo of Lee Kwang-hee

Lee Kwang-hee

Joon-seon

Photo of Lee Han-joo

Lee Han-joo

Yoon Ji-na

Photo of Nam Kyu-hee

Nam Kyu-hee

Kim Hye-yeong

Photo of Oh Woo-ri

Oh Woo-ri

Gyeong-jin

Photo of Kim Dong-young

Kim Dong-young

Oh Dong-sik

Photo of Oh Seung-jun

Oh Seung-jun

Lee Ji-won

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Reviews

B

boobeep

9/10

a girl was born with the ability to see red lines and we follow her and several characters that are directly or somewhat involved with the red lines. it was honestly rlly intriguing. i was in slump of what to watch and this hooked me from start to finish. each episode just kept hooking and surprising me. i loved seeing the dynamics on different people and how they interacted and used the glasses. it took a weird,,? turn towards the end but i loved the watching experience nontheless. i hope we get season two >< such a fun watch. contemplated reading the webtoon ver. lolol 4.5 stars !

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