As an answer to the question comes, so does a revelation. Sang-un discloses that she saw a memory of Hwal and Eul-tae together where they appeared to be friends, but disallows any room for pondering by instantly asking where it is Hwal wants to go. We then arrive at the location, a mountain that homed villagers who believed Bulgasal had lived there for 600 years. “It’s where I was born,” Hwal says, explaining to his comrade the context behind his origin. He wanted to visit one last time, before he realises his goal to kill both himself and Eul-tae, as per the wishes of Kim Hwa-yeon all those years ago. But Sang-un doesn’t want this, and begins to open up about her deep feelings for the monster she’s spent time understanding. “I can’t let you die before I find out what happened,” Sang-un then states, talking about their previous relationship that neither can fully remember.
Despite some more attempts at bargaining, Hwal is adamant that he will die along with Eul-tae, requesting that Sang-un looks after his “family” when he passes away. They then return to the safe house, and there’s a touching moment where Hwal is allowed to eat with those he holds dearest to them. It doesn’t linger, though, as the group begin to wonder about why Ho-yeol is no longer communicating with them. We then see the private detective ignore a call from Hwal, and angrily confront his former colleague over his manipulative relationship with Eul-tae.
When emotions settle down, we’re treated to a warming scene shared by Do-yoon and Hwal. The orphan is getting a group photograph printed whilst his past-life father finds himself remembering the olden days, as well as the people he has seen again after reincarnation. It culminates in Hwal telling Do-yoon to go back to school when this ordeal has finished (he had seen the youngster wishfully looking at a group of friends), and in a shift from his former actions, an agreement is made so that Do-yoon can continue living with the man he looks up to.
However, tensions soon rise again, with Ho-yeol finding himself on the receiving end of a desperate plea to kill Eul-tae given to him by his former colleague, Detective Ham. A gun is handed over, and it appears that an agreement has been made. Elsewhere, Hwal and Sang-un walk together, before the latter of the two once again insists that she should become Bulgasal again. “I’m here to end things where they begin,” she says, more adamant than ever that things should return to how they once were. Even when Hwal attempts his usual rejections, Sang-un shifts the tone, threatening to kill herself and force a change in soul owner.
With that being said, an impassioned speech from Hwal about how he can’t allow Sang-un to go, and that he has only thought about her for 600 years, stops the process dead. Back at the house though, revelations over these actions lead to more conflict, with both Si-ho and Do-yoon deeply upset. Before any further escalation, Ho-yeol returns, armed with information over Eul-tae’s location. Hwal is doubtful over this though, believing the intel is a trap, theorising that his foe wants to lock him up inside the well he intended to use for his own vengeance.
At dinner, Si-ho and Do-yoon try and create new plans, with the former saying she’ll take over the late Hye-suk’s job, and the orphan explaining his intention to return to high school. It convinces Hwal to want to find a way to live, and thanks to Ho-yeol’s apparent shooting skills, a scheme seems ready to be set in motion.
After emotionally departing the house, ready to fight Eul-tae, Hwal has a favour to ask Sang-un. He wants to return to being human, something seamlessly accepted and allowed by his accomplice, who is resigned to becoming Bulgasal once more. When the pair link up with Ho-yeol, something seems off, a fact noticed by Sang-un when she states that he doesn’t appear to be his usual self. He blames it on pressure, but it looks as though he wishes for both Bulgasals to die.
Soon enough, the trio arrive at the desired location, and Hwal instructs his two allies on what to do. Then, Hwal enters the well, seeing straight away his fellow Bulgasal, who had been waiting. Setting the surrounding area on fire, Eul-tae advances, taunting his adversary as he menacingly circles him. Yet the tension sharply turns into raw emotion, as Hwal decides to apologise, rather than attack. It leads to Eul-tae being shaken, not knowing whether to believe the words, but at the same time he’s undeniably moved. At that point, and following a further apology, Hwal strikes, initiating the fight that could culminate in a resolution.
Following a deeply intense back and forth, complete with stabbings and blood drinking, Eul-tae flits back to his calmer self, wanting to discuss the apology. He’s confused as to why Hwal still chose to attack him, and says that he must end their ongoing feud. “Get locked up in this miserable well and live an eternal life of suffering,” he solemnly says, before adding that he’ll kill Sang-un in front of Hwal first.
As Eul-tae heads towards his target, Ho-yeol intervenes, shooting the monster in the heart several times. It leaves Sang-un distraught, and she rejects the former policeman’s exclamation that both Bulgasals must die by protecting Hwal directly. As she begs, it appears that there is an element of peace returning, but before long, both Ho-yeol and Sang-un get nosebleeds, a sobering sign that Eul-tae has recovered.
Now, Sang-un walks towards Eul-tae, ready to inject him with poison. It doesn’t work out for her, though, as the menacing incarnation of Bulgasal grabs her arm and gains the advantage. Fortunately, Ho-yeol is there to intervene again, but when he hesitates in shooting by telling Sang-un to run, finds himself on the receiving end of Eul-tae’s potentially fatal stabbing.
Next, Eul-tae returns to Hwal, telling him that if he doesn’t drink human blood, it’ll take him years to recover. But that doesn’t matter anyway, as Hwal is dropped into the well, potentially trapped forever. At that point, Ho-yeol crawls towards Eul-tae, which upsets the monster as he details how the private detective always ends up involved in these matters, no matter the era, before walking off.
When we return to Sang-un, she is ready to kill Eul-tae, clinging onto hope that she can be reunited with her family. Concurrently, Ho-yeol opens up about his past to Hwal, asking why Bulgasal killed his sister without helping. But he concedes that he’s become attached to the monster, and that he cannot kill him now in spite of waiting for the chance to all his life. The private investigator, who is dying, offers his blood to a hesitant Hwal, who reluctantly accepts it once his past-life father passes away.
Because of that action, Eul-tae weakens, harkening back to Hye-suk’s prophecy about the “evil spirit that fed off its father’s blood” that will rise from the dark hole. We then see Hwal, standing fully recovered and seemingly ready for war, before we flash back to 1000 years ago. There, we see those who Hwal had been stabbed by – incarnations of Ho-yeol, Si-ho and Do-yoon – as well as the statement that he will “tear apart” those who did that to him, and drink their blood. “You are mine,” he says to the past-life Sang-un, before the episode swiftly ends.