Ep 1. Episode 1

In the first episode of Tunnel season 1, we are introduced to a grisly series of murders that have taken place in two different decades. Detective Park Gwang-ho is investigating a string of murders that have taken place in the 1980s. Meanwhile, in present day, Detective Kim Sun-jae is investigating a copycat killer who seems to be reenacting the same murders from the 1980s.

The episode begins with Detective Park Gwang-ho on the trail of a serial killer who has been targeting young women. Despite his best efforts, the killer strikes again and leaves behind a clue that leads Park to a tunnel. As he rushes to apprehend the suspect, Park is transported through time and finds himself in present day Seoul.

Confused and disorientated, Park teams up with Detective Kim Sun-jae, who is also investigating the same series of murders. Sun-jae is initially skeptical of Park's claims that he is from the past, but soon realizes that there is something strange going on.

As they work together to solve the murders, Park and Sun-jae clash over their different investigative methods. Park is a no-nonsense detective who isn't afraid to bend the rules in order to catch his suspect, while Sun-jae is more methodical and relies on modern technology to help him solve the case.

One of the biggest obstacles they face is the fact that the murders from the 80s were never solved, and they have very little evidence to go on. The killer was known for taunting the police with cryptic messages, and it seems that the copycat killer is doing the same.

As they investigate the case further, they begin to realize that there may be a link between the two killers. The copycat killer seems to have an intimate knowledge of the 80s murders, and it becomes clear that they are not just reenacting the crimes, but trying to send a message.

Throughout the episode, we get glimpses into Detective Park's life in the 80s. We see his wife and daughter, and learn about the tragedy that befell his family. It's clear that Park is haunted by the murders he was never able to solve, and is determined to catch the killer at all costs.

As the episode comes to a close, Park and Sun-jae are hot on the trail of the copycat killer. They've narrowed down the suspect pool, but they're running out of time. The killer seems to always be one step ahead of them, and it's unclear whether they'll be able to catch him before he strikes again.

Overall, the first episode of Tunnel season 1 is a tense and gripping introduction to the series. The time-traveling aspect adds an interesting twist to the typical crime procedural formula, and the dynamic between the two detectives is engaging. The mystery of the murders is intriguing, and it's clear that there are many more twists and turns to come.