S-Line: Thread of Death - When love turns into a nightmare

Introducing S-Line: Thread of Death

Original title: S라인.

Also known as: Eseulain, S Rain, S라인, 에스라인.

Writer and director: Ahn Joo Young.

Genre: Thriller, Mystery, Fantasy.

Country: South Korea

Number of episodes: 6.

Broadcast time: from July 11, 2025 to July 25, 2025.

Air date: Friday.

Original broadcast channel: Wavve.

Duration of each episode: 50 minutes.

Attractive cast in the movie S-Line: Thread of Death

Lee Soo Hyuk plays Han Ji Uk

A tough, experienced man, but haunted by the mysterious death of his wife, who committed suicide after a red thread appeared on her head. Ji Uk believes that the red thread holds a clue to his wife's death and is determined to investigate its origin. He is a talented detective but often acts recklessly, disregarding the rules to achieve his goals.

Lee Da Hee plays Lee Gyu Jin

A literature teacher with an eccentric, humorous yet mysterious personality. Gyu Jin seems to know more about the red thread than she lets on. She has a complicated past involving a love scandal, which caused her to be ostracized and transferred to teach at a small high school. Gyu Jin has a special ability to sense other people's emotions, making her an important intermediary character in the story.

A Rin plays Sin Hyeon Hop

A shy but intelligent student who has been able to see red threads since birth. Hyeon Hop sees his ability as a curse, as he often witnesses terrifying secrets in the relationships around him. He gets caught up in Ji Uk's investigation when he discovers an unusual red thread related to a murder case at school.

Lee Eun Saem plays Kang Seon A

A key figure in a tangled web of relationships connected by the thread of death.

Movie content S-Line: Thread of Death

Prologue: The Appearance of the Red Thread

The film opens with a suicide scene at a high school: a girl jumps from the rooftop after her classmates find a red thread on her head and make fun of her. Han Ji-uk is assigned to investigate the case, but he soon realizes that the death is related to a series of similar suicides in the city. During the investigation, Ji-uk discovers Sin Hyeon-hop, a student with the ability to see red threads, and Lee Gyu-jin, Hyeon-hop's teacher, who seems to know too much about the phenomenon.

Hyeon Hop reveals that he saw an unusual red thread: not only connecting two people, but also forming a complex circle, like a spider web, between many people in the school. This leads Ji Uk to theorize that the red thread is not only a symbol of sexual relations, but also a sign of a supernatural force or a larger conspiracy.

Middle Part: The Secret Is Gradually Revealed

Ji Uk, Gyu Jin, and Hyeon Hop team up, though each has their own motives. Ji Uk wants to find the truth about his wife's death; Gyu Jin is hiding a secret related to her past; and Hyeon Hop wants to escape his special ability. They discover that the red thread not only connects the living, but sometimes also connects the dead, creating "threads of death" – faint, blood-red threads that signal danger.

During their investigation, the trio discovers a secret organization behind the manipulation of the red thread, using it to blackmail, control, and pressure powerful individuals in society. The organization appears to be involved in an advanced biotechnology that can interfere with the human mind. Gyu Jin reveals that she was once part of this research project, but fled upon discovering its dark purpose.

Climax: Confronting the Truth

The climax of the film occurs when Ji Uk and Hyeon Hop infiltrate the headquarters of the secret organization, where they discover that the red thread is actually a supernatural parasite, activated through a technology implanted in the human brain. The leaders of the organization use the thread to control relationships and manipulate society, with the goal of creating a new world order.

In a tense confrontation, Gyu Jin sacrifices himself to destroy the organization's technological core, stopping the spread of the red thread. Hyeon Hop, with his special ability, helps Ji Uk find a way to cut the death thread that connects the dead, freeing the souls of Ji Uk's wife and other victims.

The End: Liberation and Unanswered Questions

The film ends with Ji Uk standing in front of his wife's grave, the red thread missing for the first time. Hyeon Hop decides to learn to live with his ability, using it to help those trapped in toxic relationships. However, the final scene shows a new red thread appearing on a supporting character's head, hinting that the threat may not be over yet.

S-Line: Thread of Death movie showtimes

S-Line: Thread of Death consists of 6 episodes, each episode is 50 minutes long. S-Line: Thread of Death's broadcast schedule is as follows:

Note: Showtimes may vary by distributor.