In 2018, sixty-two days before Hyun-jo joins the Jirisan ranger team. A lone hiker treks on the mountain and passes by some yellow ribbon trail markers tied to various tree branches. As he passes out of sight, someone dressed all in black quietly goes about moving the ribbon markers to different branches.
A new hiker comes along the path and carefully follows the trail markers. As he treks onward, we get one last glimpse of him — with the figure in black following behind him.
Yi-kang visits the police station, to the surprise of KIM WOONG-SOON (Jeon Seok-ho). Yi-kang gets straight to the point, asking if Woong-soon knows anything about the case of Yang Geun-tak, the missing hiker that Yi-kang knew the location of.
Woong-soon flips through the case file’s photos and tells Yi-kang he’d heard it was declared an accidental death. Yi-kang asks if he knows anything about the yellow ribbon that was found with Yang’s remain. He replies that he’s just a low-ranking officer so he wouldn’t know more about it, but figures that the case being closed means everything looked normal. He hesitantly asks if she found something strange about the ribbon.
Da-won enters the office and marvels at how Yi-kang was able to clean the station and organize the files — even documents Gu-young put off doing for a month. Gu-young defends himself, saying patrols and rescues kept him busy. Da-won abruptly asks if he and Yi-kang are really the same age, implying that he looks older. Gu-young scoffs and says that he’s technically younger by a few months.
Dae-jin finds Yi-kang reviewing CCTV footage of Jirisan and asks if she’s looking for the trail marker. He still thinks it’s a coincidence and probably a prank. Yi-kang counters that Jirisan is huge and the marker pointing towards the missing hiker is too exact to be a coincidence.
Beyond the marker, he can’t understand why she was even looking at photos of Jirisan when she’d nearly died and had been hospitalized for a year. Was it because of Hyun-jo? Yi-kang remains silent but glimpses of a winter’s day flash by.
A rock coming down on someone’s head with a splatter of blood against snow, Yi-kang looking terrified then a fall in the snow, a bloody Hyun-jo lying on the ground, and Yi-kang being carried off unconscious on a stretcher.
Dae-jin continues to probe, and asks what prompted them to climb Jirisan that day. She finally responds, only to state simply, “Nothing. We only tried to protect the mountain. Because that was our job.”
Hyun-jo packs some gear and his ranger ID before heading out. Il-hae stops him to ask if he’s headed to Jirisan on his day off Hyun-jo replies that he’s headed to there to do some training.
Il-hae wonders why a Seoulite like Hyun-jo opted to be stationed at Jirisan instead of a mountain in the city. Hyun-jo asks if Il-hae lives nearby and Gu-young comes out to say that Il-hae wouldn’t be at the dormitory eating ramyun if he did. They start arguing over patrolling and ramyun, and Hyun-jo quickly leaves.
As Hyun-jo hikes, he finds a pair of glasses and wondering if the owner of said glasses was able to get down the mountain safely without them. He reaches the summit and savors the mountain vistas that surround him. Hyun-jo takes a sip of water but suddenly freezes. Another vision flashes before his eyes, this time glimpses of yellow ribbons hanging in the dark and finally, a bloody hand.
Yi-kang is helping out at the restaurant her grandmother LEE MOON-OK (Lee Young-ok) runs. While she’s busy serving and cooking scallion pancakes Grandma is busy shooting the breeze with Yi-kang’s coworkers. She shares that Yi-kang was once hit by a motorcycle when she was young, but she didn’t even shed a tear and just ran to the mountain. Even as a young girl, Jirisan was a refuge for Yi-kang, and it’s where she’d run to whenever she was upset. Yi-kang exasperatedly tells her grandmother to stop slacking off but Grandma says she’s keeping the customers happy.
Dae-jin’s arrival cuts their argument short and despite her frustrations, Yi-kang obediently goes back to making more pancakes. Hyun-jo calls (he’s saved as “Crazy Guy” on her phone) asking questions about a pine tree habitat with yellow ribbons. Yi-kang says it must be a restricted area then, since illegal hikers are the ones who use yellow ribbon trail markers. She lets him know that there’s one a few kilometers away from Mujin Valley but when she asks him if he’s working on his day off he just thanks her and hangs up.
Hyun-jo sets off for a new destination and he hikes into a foggy area. He takes in his surroundings carefully, as if he’s trying to match the location to his vision. It’s eerily quiet — but he’s not alone. A man pops out to confront Hyun-jo and asks why he’s being followed. Hyun-jo counters by saying that he should be asking the questions. He asks the Lone Hiker if he has permission to be in this area. The Lone Hiker gets combative, and tells Hyun-jo he can go wherever he wants. Hyun-jo identifies himself as a ranger and offers to guide the Lone Hiker out of the restricted area and down the mountain.
The Lone Hiker responds by eyeing Hyun-jo and noting that he’s not in uniform and has no partner with him, which means he’s off-duty. He dismissively tells Hyun-jo to just let him be, but his knowledge of rangers and their work just makes Hyun-jo more certain that something nefarious is afoot. The hiker resignedly hands over his backpack to be checked for any poached goods then admits that he is searching for something — the body of his father, who went missing on Jirisan a year ago.
That night, everyone is gathered at the town hall where a memorial is set up. Hyun-jo asks what the memorial is for and we learn that in 1995 there was a torrential rain during the summer peak season, which caused a huge flood. Over a hundred people died, both rangers and vacationers alike. In flashback, we see covered bodies gathered in a large room with family members grieving over them. Young Yi-kang stands alone, looking grief-stricken.
Hyun-jo finds Yi-kang in her usual solo hangout spot (thanks to a tip-off from Grandma). He tells her about his encounter earlier at the pine tree habitat and shows her a case file. It’s for a missing person, Hong Sang-gyu. He’d been deep in debt with a failed business when he disappeared. The authorities were unable to trace him and the case was closed soon after he’d been declared missing. He tells her that the son hasn’t given up and he wants to help. Yi-kang is more pragmatic, after all the search may have been called off because there was no evidence that the man had even come to Jirisan.
But Hyun-jo is convinced that Hong Sang-gyu met his end in Jirisan, and entered a restricted area, possibly through Mujin Valley. Yi-kang replies that Mujin Valley is huge and that he should just give up. She warns him not to go on the restricted trails when he’s off duty. Hyun-jo confides that he saw the marker again, just like the time they found Seung-hoon and he saw someone bleeding, it might be the Lone Hiker. Yi-kang takes that information in…and concludes that he must be drunk. Hyun-jo doesn’t try to persuade her and just resignedly tells her to head back to the memorial.
In the morning, Hyun-jo seeks out the Lone Hiker to find out why his father went to Jirisan. The son shares that Hong Sang-gyu was a landscaper and was obsessed with trees, particularly pine trees. The day he disappeared, he’d planned to go see the pine trees on Wusong Cliff.
Hyun-jo promises to patrol that area and the Lone Hiker pleads to go with him. Hyun-jo reminds him that the area is restricted. The Lone Hiker says it would be easier to search together so they can skip any areas he’s already searched. He gives a heartfelt plea, saying he wants to be the one who find his father.
Elsewhere, at Jirisan, a young woman checks her lottery ticket and finds that she’s holding a winning ticket. She holds it up in excitement but a sudden gust of wind blows the ticket away. She approaches Il-hae to ask for help in finding the ticket, but he says that’s not part of his job. She explodes, saying the winning prize is 1.4 billion won (a little over a million dollars). Everyone within earshot hears it, and everyone scrambles off to look for the ticket.
The rangers try (and fail) to keep visitors out of restricted areas. With so much money on the line, people are desperate to find the lottery ticket and the news has already spread to other parts of the park. Even Yi-kang seems interested, when she hears how much the ticket is worth.
She hops a fence and joins the trespassing visitors. Just a few seconds later, Yi-kang shouts that she’s found it, and holds the ticket up victoriously. She hands it to Il-hae, telling him to return it to the owner. It’s actually just a receipt, but her ploy works and the rangers get to work fining trespassers and ushering them out of the restricted area.
Yi-kang catches a pair of hikers attempting to leave with an illegally harvested endangered plant, and while writing up the violation, she suddenly remembers Hyun-jo. Another ranger tells her that he could have gone to Mujin Valley since he had been looking for documents about it earlier.
Hyun-jo and the Lone Hiker reach Wusong Cliff but the son says he’s already searched the vicinity for a whole year, his rationale being that his father might have committed suicide. Hyun-jo consoles him, saying he’s sure they’ll find his father.
At the police station, Yi-kang asks Woong-soon about Hong Sang-gyu’s case. Woong-soon remembers it and tells her that the daughter had visited a week ago to ask if they had found her father yet. Yi-kang comments that the children are trying hard, and that his son has even been scouring Jirisan himself. At that, Woong-soon quizzically states that Hong Sang-gyu doesn’t have a son.
Woong-soon’s prints out Hong Sang-gyu’s ID report and on a far wall there’s a picture of the man with Hyun-jo is with. The photo lists him as KIM KI-CHANG (Kim Min-ho), a fugitive wanted for fraud.
Back on the cliff, Ki-chang and Hyun-jo discuss where to head next. Hyun-jo references the case file and states that there was a heavy downpour on the day Hong Sang-gyu went missing. A satellite image shows that the flow of the water changed over the year because of that.
Hyun-jo identifies a section near the newly-formed waterway for Ki-chang to check and hands him a GPS device. Hyun-jo plans to do some searching along the cliff’s rock face. Since there’s no cell reception at their location, he suggests they regroup in an hour at the location he marked in the device. Before they separate, Hyun-jo asks what his father was wearing. Ki-chang says he was wearing a green windbreaker, gray pants, and had a black backpack.
Hyun-jo rappels down the cliff. While he scans the area around him, he spots something off in the distance: a black backpack hanging from a branch.
Yi-kang visits Hong Sang-gyu’s house to meet his daughter, Young-mi. There’s a majestic looking pine, with large, twisted branches in the front yard. Young-mi seems incredibly nervous when Yi-kang introduces herself as a ranger, which doesn’t go unnoticed. Yi-kang asks about the pine tree, but Young-mi claims to know nothing about it.
Yi-kang comments that the pine tree couldn’t have grown nearby because only strong clifftop winds could have shaped its branches. To illegally harvest that one tree would have required great sacrifice, with hundreds of other trees being cut down to create a path for it. She notes that it would take decades for nature to recover but illegal harvesters never care. After all, a single tree would net them nearly $100,000. The more Yi-kang talks, the more anxious Young-mi gets.
When Yi-kang asks flat out if her father went to the mountain the day he went missing because of a pine tree. Young-mi hesitates, then responds that her father didn’t want to do it, but loan sharks kept hounding them. They needed the money desperately, so he had no choice. That’s why she couldn’t tell the police then, she had been afraid her father would end up in jail. Yi-kang asks who had recruited her father to do the harvesting.Hyun-jo and Ki-chang meet up and neither man has found anything so they continue their search in another area. Meanwhile, Yi-kang tries to call Hyun-jo but he’s in an area with no reception. She recalls her earlier conversation with Young-mi and her revelation that Kim Ki-chang was the man who intimidated Hong Sang-gyu into poaching.
The sun is setting and Hyun-jo calls it a day. Ki-chang gets disgruntled and accuses Hyun-jo of stalling and leading him in circles. What’s the plan? To call the police? Hyun-jo states he will if he has to, and asks a question: How did he know exactly what Hong Sang-gyu was wearing when he went missing? It was swelteringly hot that day, he would have only worn his windbreaker at the top of the mountain.
He pulls out something to show Ki-chang, and it’s Ki-chang’s own wallet. It turns out that Hyun-jo had managed to retrieve the bag he saw hanging near the cliff and inside had been Ki-chang’s wallet with his driver’s license. He questions why Ki-chang’s things were on the cliff and if Hong Sang-gyu actually committed suicide.
Eyes full of rage, Ki-chang confesses there was no suicide, then slashes Hyun-jo with a knife. They struggle, but Ki-chang manages to stab Hyun-jo and makes off with the sole GPS device.
Interspersed with their fight, are flashbacks to Hong Sang-gyu’s last day alive. He and Ki-chang and had been together on Wusong Cliff, along with a client.
Ki-chang had received 50 million won in cash on the spot, and the pine tree was to be taken down from Jirisan. The two men fought, with Hong insisting this would be his last job. He had taken the cash and Ki-chang chased him, then pushed him off the cliff’s edge. As Hong fell, the money bag fell with him.
Hyun-jo staggers to his feet and struggles along the trail with only a flashlight to guide him. He sees yellow ribbons on the branches and when his bloody hand grasps at a rock wall, he realizes that he had seen himself in his earlier vision. As he collapses to the ground, he slams a twig between stones to create a marker and loses consciousness.
As Ki-chang tries to navigate his way in the dark, he’s found by Yi-kang and he claims to merely be a lost hiker. She scoffs and tells him that she’s not like the too-nice-rookie, she knows a crook when she sees one. Ki-chang attempts to threaten her but Yi-kang coolly tells him that she knows to hike with a radio. At that, her reinforcements come out from the shadows; it’s Woong-soon with a partner, and Gu-young and a few other rangers.
Rewind to four hours earlier, Yi-kang had radioed the team to meet her at the pine tree habitat and she’d set off to find Hyun-jo. When she reached him, he was bloody and unconscious but his trail marker had led her to exactly where Ki-chang was wandering.
At the hospital, Hyun-jo checks out a commendation plaque the police chief has bestowed onto the ranger team. Yi-kang asks Hyun-jo if he’s really psychic, in response he asks if she’d believe him. She replies that she doesn’t trust people easily, so she’ll wait and see what the truth is. As she heads out, Hyun-jo stops her to say that he was able to narrow where Hong Sang-gyu might be. Though she believes death is the end, he disagrees with her and says he thinks Hong’s family would agree with him.
Yi-kang leaves, and at Jirisan, she heads into a restricted area. Day after day, she treks and marks off areas along the way. At one point, she hears someone crying. It’s the girl who lost the lottery ticket, and she’s lost and injured. Yi-kang helps her, berating her for being reckless and putting her life in danger for the lottery ticket. The young woman says that she’s never had such luck and needs to find it because she wants to buy her mother a house.
Yi-kang continues her search and at long last finds Hong Sang-gyu’s remains. She pours out an offering of soju, lights incense sticks, and prays. Young-mi is waiting when her father’s remains are brought out from the park. Yi-kang returns her father’s bag to her and Young-mi sobs as she hugs her father’s bag.
Memories of Yi-kang’s own loss flood her mind, and we see both the day her parents had passed as well as the funeral and a fight young Yi-kang had had with her dad.
2020
Da-won shares attempts to share an egg sandwich with Yi-kang. She’s thrilled that Yi-kang knows her name, considering what a legend Yi-kang is. Da-won chatters away and offers to help look for more markers, but Yi-kang’s complete silence prompts her to get up. Before she can leave, Yi-kang asks if she’s still going on patrol at Dowon Valley the next day. If so, Yi-kang asks a favor of Da-won: Create a marker in the valley, which would point to the station. Da-won agrees and Yi-kang draws the exact formation she should make.
Dae-jin later approaches Yi-kang and informs her that he found her a spot for her at the rangers’ headquarters. She protests but he says it would be hard for her to continue working at the station. He promises to let her know first if he finds anything about the mark. Smiling, he tells her to head to HQ and walks away without giving her a chance to speak.
While on patrol, Da-won creates an excuse to sneak away while Gu-young is distracted. She reaches the exact location Yi-kang described and starts to set up the trail marker.
Back at the station, Yi-kang looks through more case files, and spends time examining photos of the yellow ribbons. She recalls a time when she and Hyun-jo had been searching for illegal hikers. They had been looking at red ribbons which are usually set up by illegal hikers to mark the path to the summit for any stragglers. Hyun-jo remembers seeing yellow ribbons the time he was stabbed and tells her that it was strange, the ribbons all lead away from the summit, as if someone was trying to get people lost.
Back in the present, Yi-kang takes a call from the Jeonbuk Regional Office, requesting a report file that’s needed urgently. She looks through the drawers — and finds a plastic bag filled with yellow ribbons, stained with blood.
At Dowon Valley, something catches Da-won’s eye. A thick fog descends rapidly over the area.
She stoops down to takes photos of a flowering plant but stops in shock when a cloaked figure steps in front of her. Something (blood?) drips down on the figure’s boots. The cloak is bloodstained and dirty, and it says “Korea National Park Service.”
Underneath that cloak’s hood, two eyes stare out from a dark void.