Episode 20 of Mouse is the longest chapter of the series, clocking in at a whopping 1 hour 40 minutes. It’s basically a film, let’s be honest, but it seems we’re on track for some solid answers here.
The episode begins with Ba-Reum confronting Choi Young-Shin, showing up in her apartment. She mentions the abortion bill and how it was rejected. This is what started her crusade, convincing Daniel Lee to a longer-term solution. They intended to use these fetuses as evidence to prove the psychopath gene.
The Soo-Ho situation was a mistake and it completely destroyed the man. He never intended to go that far nd was wracked with guilt over what happened. Apparently Ba-Reum’s actions caught her off-guard but she continued to use this OZ organization to keep tabs on him, realizing it would be easier to pass the bill if he clocked up a lot of deaths.
Choi admits that she’s a scientist and her ultimate goal is to create a utopian world free of psychopaths. The “Land of Oz” as we soon come to learn.
Having heard enough, Ba-Reum holds a gun up to her head. She demands he fire, rasping that those with the psychopath gene deserve to be killed.
Meanwhile, Moo-Chi shows up at the house and finds Choi tied up and kept alive in the closet. Ba-Reum decided against killing her and has left. This is enough for police to arrive and take her away. With Ba-Reum still on the run though, Moo-Chi listens to his voicemail and hears Bong-Yi heading off on the hunt.
Anyway, Bong-Yi was taken by Ms Kim, who intended to keep her safe incase Oz kidnapped her. Ba-Reum shows up in the rain and the two wind up face to face.
Bong-Yi comes at him with a knife, swinging frantically and trying to kill the murderer. She’s understandably upset but Ba-Reum sidesteps her and drops to his knees.
He pleads with Bong-Yi, asking that justice be served and he be allowed to hand himself in. Eventually he gives up but just before Bong-Yi pierces his face, she remembers him killing Duk-Soo for her and stops. She wants him to atone for his sins and live his life in regret. She drops the pole and walks away, listening as Ba-Reum’s cries pierce the air. Ba-Reum eventually hands himself in to the police.
The crowd are enraged, lusting for blood as everyone watches him head into the station. Among those is Hong-Ju, whom we see was working with Daniel Lee after finding him in Yo-Han’s basement.
Daniel Lee is eventually brought in for questioning but he doesn’t talk. At least not to begin with. He encourages Yo-Han’s Mother to see Ba-Reum, especially as he happens to be her real son.
She heads in to see Ba-Reum and admits that they switched babies. After what Soo-Ho did to Jae-Hoon’s family, Sung Ji-Eun was convinced her son was responsible and this sparked her into trying to find him. Only, his “aunt” got to him first and with his ID and name changed, she found herself searching everywhere for Ba-Reum but failing. She was badly affected by the serial killings and instinctively knew it was him.
After the surgery she realized he was different and couldn’t bring herself to kill him. Still, she’s obviously overcome with grief and it’s made worse by the echoing remnants of Seo-Joon’s sneering remarks about bringing an offspring into the world; a mini “Head Hunter” as he refers to him.
Moo-Chi heads back into the prison and confronts the Head Hunter, finding out the truth about Ba-Reum’s lineage. He eventually calls the man dumb and brings up Choi Young-Shin. This certainly takes the smile off the Head Hunter’s face as he curses the scientist.
During further flashbacks we learn Yo-Han conducted a DNA test and found out the truth about who he is. He didn’t kill Ji-Eun but did knock her out long enough for him to slip away and find Ba-Reum. Now in the present, Ji-Eun tellingly calls Yo-Han her son while looking out at the sea.
Things take a turn for the desperate when Ba-Reum’s aunt goes missing. Given she has crucial evidence linked to what happened with Ba-Reum, he implores Goo-Reum to do his best to find her.
Only, Detective Lee Min So has gone missing too. With Choi arrested, the group have a difficult 48 hour window before she’s free to go. That window is moved up to right now though when Choi’s arrest warrant is rejected and she’s free to go.
This quickly backfires when Hong-Ju does her show and reveals damning evidence against Choi Young-Shin and the Oz organization. Daniel Lee testifies while Ms Kim shows up too! It turns out Lee Min-So managed to keep her safe to avoid Choi sending her goons after her.
While Ba-Rum gives his confession, Sherlock Hong-Ju blows the case wide open, with photos of victims and even audio evidence of Choi incriminating herself and claiming the number of victims aren’t enough. This is enough for her to be arrested and face her crimes.
Yo-Han meanwhile is completely freed of any charges, thanks to several confessions from the victims and a video of him sobbing. Given psychopaths don’t show this sort of emotion in private, it’s enough for him to be let off the hook.
The final swansong comes from Hong-Ju, who admits she worked with Daniel Lee to have Ba-Reum kill Duk-Soo. She also admits to killing someone 26 years ago. This is, of course, when she was a child and lead Soo-Jung out to a car.
Symbolically, it’s Du-Seok who arrests Hong-Ju. She apologizes for having a hand in this and is eventually taken away in handcuffs. This all leads nicely to Oz organization being taken down and investigated thoroughly for putting personal greed ahead of the sake of the people.
Ba-Reum’s court case goes ahead and it’s agreed unanimously that he live the rest of his days in isolation. His execution has also been agreed too for an unspecified period in the future.
We then jump forward 6 months later. Ba-Reum is led out through the yard where the Head Hunter notices the look in Ba-Reum’s eyes have changed. Well, Ba-Reum is cold and heartless, showing no remorse for his actions. However, it does bring him face to face with his father.
He claims they have superior genes and tells Ba-Reum to keep the look in his eye. As he steps forward for a hug, Ba-Reum plunges a knife into his Father, repeatedly stabbing him and letting the man bleed out on the floor.
This, as it turns out, was his plan all along and he convinced Dong-Koo to allow him entry so he could rid the world of the Head Hunter. In fact, he cuts his head off too; symbolically this is what Moo-Chi actually wanted and threatened him with all those episodes ago.
Anyway, Moo-Chi hears the news – and also that Ba-Reum is badly suffering and could well die soon. Du-Seok convinces him to show up and see him before he dies.
Moo-Chi gives the boy a piece off his mind, mentioning how he’s never going to forgive him and he’s only there to see how pathetic he is. Ba-Reum drops his head and apologizes. Moo-Chi notices the emotion in his eyes and tells him to do his best to help the victims’ families. He sobs, admitting that he misses Bong-Yi.
Moo-Chi brings the girl in, who’s burning with anger and demands that he suffer the worst fate imaginable. He tells Bong-Yi that he hopes in his next life he’ll be born as an ordinary human being.
Interestingly, Ba-Reum finds himself back in a church again; a throwback to his moments as Jae-Hoon praying that he’s not a monster. He symbolically sits with his younger self and tells him he’s no longer a monster. This eventually serves as the end of Ba-Rum, who dies in extreme pain and misery for his sins.
We then jump forward 3 years later. Despite protests from the people, Choi is given a pardon from prison. This is apparently done by the Blue House as a way of granting a union in the future. Only, when she arrives at the parking garage, the driver stops the car and brandishes a knife.
Meanwhile, Hong-Ju and Moo-Chi sit together and apologize to one another. This eventually sees Moo-Chi head back to the prison and says his last goodbyes, visiting Ba-Reum’s gravestone.
Mouse bows out with a strong finale, one that works to tidy up all the loose plot threads and explain away most of what’s happened. The extended run-time really helps to give this final episode some breathing room, and given the number of twists along the way Mouse does the best it can to tie everything together.
However, there’s a part of me that wishes this drama was only 16 episodes. Without the Oz organization and government intervention this series works nicely as a character study of a psychopath who gains emotions and must repent for what he’s done. Despite that, this has been an undeniably epic watch both in terms of scope and storyline.
At the center of this though are both Lee Seung-Gi and Lee Hee-Jun who put on excellent performances in their lead roles. The fact that by the end of the episode you actually feel sorry for Ba-Reum is testament to the good acting on display.
In a way, Ba-Reum was granted his wish of being given emotions but it was done at the expense of being forced to suffer for everything he’s done as Jae-Hoon.