The show will tell the story of a mysterious red line that appears above people’s heads, connecting them to those they’ve had sexual relations with. Han Ji Uk is a detective who wants to discover the truth about the mysterious red line. Gyu Jin is a quirky high school teacher and Hyun Heup is a high school student who has been able to see the red line since birth.(Source: NME Asia) ~~ Adapted from the webtoon "S Line" (S라인) by Little Bee (꼬마비). ~~ Release dates: Apr 27, 2025 (Episode 1-2 premiere | Festival)