S Line's last two episodes starring Lee Da-hee, Arin, and Lee Soo-hyuk were released on Friday, July 25, 2025. The Wavve series depicted the tale of a girl, Shin Hyun-eup (played by Arin), who could see red lines connecting people's heads. The red lines represented a person’s s*xual relationship with another person.By the end of S Line episode 6, it was revealed that Lee Kyung-jin (Lee Da-hee), Shin Hyun-eup’s teacher, could also see the red lines without the glasses. Lee Kyung-jin was the one who gave people these glasses and voiced their evil desires, which led to several deaths.Lee Kyung-jin showed them the red line could disappear if their s*x partner died. With this, people who have multiple S lines began to kill their partners. In the final episode of S Line, Lee Kyung-jin lured Shin Hyun-eup to the school by kidnapping her friend Oh Kyu-jin.Shin Hyun-eup soon realized they were trapped in an illusion, as she and Oh Kyu-jin could not leave the building. Shin Hyun-eup saw a cult of people following Lee Kyung-jin, who had murdered their partners. Lee Kyung-jin stabbed Shin Hyun-eup as she refused to partner up with her in this trap.The blood that was shed from Shin Hyun-eup's body started to rise up and turned into a huge red ball. The ball burst and turned into red lines, which were now visible to everyone. At the end of S Line season 1, people got accustomed to the lines and learned the purpose they served, but were still unaware of how they emerged.Shin Hyun-eup became an outcast again and visited Joon-sun's grave. She heard someone calling her name, and it was Lee Kyung-jin. There is a high possibility of a second season, as Lee Kyung-jin’s surprising return in Shin Hyun-eup’s life leaves a series of questions.S Line ending explained: Han Ji-wook learns a shocking truth, and Shin Hyun-eup sees her mother in Lee Kyung-jin’s cultIn episode 5 of S Line, Han Ji-wook (Lee Soo-hyuk) used the glasses to solve a minor girl's s*xual assault case. Ji-na filed a complaint against a boy named Han-yu and accused him of drugging her and assaulting her. Han Ji-wook noticed she had four S lines, but she said she had never had sexual relations before.Han Ji-wook believed she was lying, and the evidence pointed against her, which almost led to the closure of the case. However, on further investigation, it was revealed that four of Han-yu’s classmates had assaulted Ji-na at his place.Although he was not involved in this act, he was the mastermind who planned to drug her and call his classmates. By the end of episode 5, Han Ji-wook saw Lee Kyung-jin kidnapping his ill father, who was admitted to a hospital. He received a photo of Kang Seon-a (Lee Eun-saem) and rushed to Seon-a’s hospital.Han Ji-wook saw the red line on Kang Seon-a's head moving, indicating that the person she slept with was approaching her hospital room. Han Ji-wook pulled out his gun and turned around to see his father, Kang Seon-a, and grandfather entering the room. Han Ji-wook was shocked to see his father's S Line connecting to Kang Seon-a. Han Ji-wook attacked his father but could not beat him.Meanwhile, Shin Hyun-eup liked Joon-sun and suggested they sleep together, as he was special to her. Joon-sun and Shin Hyun-eup’s red lines connected. However, before they left for their home, Joon-sun met with an accident and could not make it. Shin Hyun-eup received an anonymous message with a photo of Oh Kyu-jin trapped at the school. She called Han Ji-wook and asked for help.Shin Hyun-eup told him she received such messages every birthday, but nothing ever happened. However, the picture of Oh Kyu-jin made her believe that something huge was coming their way this time. The two reached the school; Shin Hyun-eup went to Oh Kyu-jin, and Han Ji-wook reached the rooftop.Also read: “We got 3 kissing scenes in just 1 episode” — Fans stunned after 'My Girlfriend is the Man!’ premiere starring ASTRO’s Yoon San-ha & OH MY GIRL’s ArinHan Ji-wook saw an illusion of Lee Kyung-jin leading a cult of people killing their partners, and a huge number of red lines could be seen on her head. He saw his father tied to a table in front of Lee Kyung-jin. Han rushed and tried to undo the knot, but Lee Kyung-jin gave him a knife and told him to kill his father to save Seon-a.As he took the knife, she stopped him, pushed him away, and stabbed his father in the neck. Han Ji-wook got up and tried shooting at her, but the bullets could not reach her, because no ordinary person could kill her.At the same time, Oh Kyu-jin and Shin Hyun-eup also reached the rooftop. Shin Hyun-eup saw that Oh Kyu-jin also had the glasses and started acting strangely after using them. Oh, Kyu-jin told her that Lee Kyu-jin was the one who gave her the glasses. Shin broke the glasses, and Oh Kyu-jin returned to normalcy.However, Shin Hyun-eup's eyes turned grey. She also entered Lee Kyung-jin’s illusion. At one moment, Shin’s mother appeared when Lee Kyung-jin was trying to attack her. Her mother said that she also had the glasses that Lee Kyung-jin gave her.Those glasses were the reason why she killed her husband and assured Shin Hyun-eup that it was not her fault. The last episode of S Line showed how the world was filled with red threads.Also read: Will Kuina and Chishiya return in Alice in Borderland 3? Confirmed cast lineup so far exploredS Line season 2 renewal possibilities exploredLee Eun-saem as Kang Seon-a and Lee Soo-hyuk as Han Ji-wook (Images Via Instagram/@wavve.official)After the emergence of the red line in S Line episode 6, everyone could see them and learn about other people’s secrets. Kang Seon-a recovered, and her red line disappeared after Lee Kyung-jin killed her grandfather. Han Ji-wook picked her up from school as usual, and she told him it was embarrassing to be around him because of his S Line.Meanwhile, Shin Hyun-eup continued to live her life alone until Lee Kyung-jin showed up. With the new development, particularly with the red lines, there are many stories that can be explored. Lee Kyung-jin and Shin Hyun-eup's rivalry may also be further explored. This raises the chances of a second season; however, the production team of S Line or Wavve has not made any official statement on the same.All six episodes of S Line are available on Wavve for streaming.