In the modern world of the 21st century, there are still dangerous places. Nature cannot be tamed, and willingly entering a wild area means opening yourself to the same dangers as people three centuries ago. A mountain bows to no one, least of all the puny humans who clamber over it for amusement. Injury, illness, and exposure are serious problems, and people who suffer them will likely die without help. This is the backdrop of TvN’s drama Jirisan. Set among the park rangers stationed on the titular mountain, Jirisan is a thriller that threads the needle of grounding itself in the genuine dangers found on a mountain and leaning into the otherworldly things many of us city people suspect the wilderness of preserving to this day. 

Spoilers Ahead

While technically split into two timelines, the drama as a whole is anchored by the bond between veteran ranger and local Seo Yi-kang (Jun Ji-hyun) and her new partner, Kang Hyun-jo (Ju Ji-hoon). Jirisan starts when their partnership starts, following Hyun-jo as he is thrown into his new job– literally being thrown a pair of decent boots as there is a time sensitive search underway for a missing boy. It’s when the search team splits into pairs, with Yi-kang getting the rookie as she ran off her last partner, that Hyun-jo reveals why he became a ranger: for months, he’s been getting psychic visions of people who died on the mountain, and figured he should use them. The show then flashes forward 18 months, revealing Yi-kang is now in a wheelchair, Hyun-jo is in a coma, and nobody knows what happened.

This sets up the drama moving forward; with the show lurching back and forth between two timelines at unpredictable moments. The result is a story told in parallel, showing the present and the past working together to solve a single mystery: the identity of a serial killer preying on those who hike Jirisan. Yet, the tone between the two halves is strikingly different. In the past, Hyun-jo is attempting to solve the mystery because he feels an altruistic obligation to find this killer. Yi-kang claims to have the same motivation in the present, but as the series goes on, it becomes clear that her true reason is first to avenge, then to save, Hyun-jo.

Their relationship is the glue of the entire series. Yi-kang is abrasive and impatient, called Demon Seo by her teammates, but respected for her skills as a ranger. She’s dismissive of Hyun-jo until he tells her that he was career army, and thus used to danger, risk and hardship. Moreover, they both are willing to risk their own lives to save others. After a baptism by fire, the two form an immediate bond based on equal standing and mutual respect. Even as Yi-kang dismisses his visions, she trusts him and his judgement impeccably, with that trust quickly blooming into a fierce friendship.

It is that friendship that drives her in the present day. When Yi-kang notices an old code that only they used– using rocks to indicate the location of injured hikers by recreating landmarks– she returns to the mountain, assuming that someone is attempting to communicate with her. When she learns that someone is Hyun-jo’s spirit, bound to the mountain as his body lies in a hospital, she then becomes hell-bound to solve the murder, believing that imprisoning him will free his spirit. Yi-kang risks her own life to save his, and Hyun-jo’s attempt to communicate with her border on mania. While it can be debated as to whether their relationship is romantic or platonic, what it is without question is intense and compelling.

Then there’s the true star of the show: Jirisan itself. While a fantasy murder mystery, Jirisan pulls no punches with how dangerous a mountain is, and how few people seem to appreciate that. While many of the rescues and deaths that occur on the mountain are the act of human malfeasance, there are plenty caused by stupidity, ignorance, and entitlement. A recurring issue is people entering the restricted areas to hike, poach, or gather herbs, then claiming they have a right to do so because their families have lived in the area for generations. There is little regard for conservation or safety, leaving the rangers fighting an uphill battle. Even the inciting incident for the murders can be traced back to the strengthening of the park service and cracking down on environmental violations. 

And the mountain does not care about any of this. Nature is untamed, leaving the rangers fighting to save the innocents on the mountains from snow, typhoons, fires, and flash floods. Yi-kang lost her parents in one such flood as a teen, eventually becoming so desperate she went up the mountain herself in a last-ditch effort to find them. One ranger does die as a result of the murderer, but another passes in the line of duty while rescuing an illegal hiker. Jirisan casts no judgement on who is there or why; nature is equally cruel to all who cross her. 

And keeping the entire show going forward, mixing the friendships with the murders and the everyday risks, is the writing of Kim Eun-hee. Well known for Three Days, Signal, and Kingdom, she is a master of timeline manipulation, tightly woven adventures, and the risks of foresight. One of her earliest strokes of genius is when Hyun-jo himself is stabbed– an event that happened only because he saw a vision of someone dying and set out to stop it; only to find the victim was himself and if he’d done nothing, nothing would have happened. 

Moreover, she is not trying to outsmart her audience. There are no sudden swerves that don’t make sense with the previous information, just put in there to surprise the audience. There isn’t additional information given to the viewers, leaving us railing as the characters follow what we know are dead ends. Instead, we are limited to the same knowledge as Yi-kang and Hyun-jo; sometimes less, given the dual timelines. We are following the same path as them, tracing the same leads and feeling the same risks.

Jirisan is a rollercoaster of a thriller. Balancing supernatural elements with natural and manufactured danger, it grips the audience as we struggle in vain to figure out what is happening and why. And with both Jun Ji-hyun and Ju Ji-hoon turning in star performances, the human element is just as visceral. I mean, some of you have never tried to drag your injured body onto a mountain with your bare hands in a desperate attempt to see the spirit of someone you love, and it shows.

(Images via TvN, YouTube)