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Series / Mouse (2021)

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Mouse (마우스, Mauseu) is a 2021 South Korean thriller series starring Lee Seung-gi, Lee Hee-joon, Park Ju-hyun and Kyung Soo-jin.

A serial killer is on the loose. Police officer Jeong Ba-reum manages to track him down. Afterwards Ba-reum begins to wonder how someone could become so evil. With his colleague Go Mu-chi he sets out to understand how psychopathic behaviour develops. But their quest for the truth begins to raise some very poignant questions. Questions that lead them to wonder, where does one draw the line between far and too far?

The series can be watched on Viki with English subtitles.


Contains examples of:

  • Accidental Murder: Su-ho didn't realise there was anyone still in Jae-hoon's house when he set it on fire. Unfortunately Jae-hoon's brother was still inside.
  • Adult Fear: This might as well be called "Adult Fear: The Series".
    • Mu-chi's mother sees the serial killer trying to break into the van where her children are hiding. She leads him away, but after he kills her he goes back and almost kills her sons.
    • Ji-eun learns her husband is a serial killer and her unborn baby has the psychopath gene. When her son's born he grows up to be a serial killer too.
    • A woman takes her son to an amusement park. He disappears and she gets a ransom demand. Then she learns the kidnapper is a serial killer who's threatening to kill her son unless Mu-chi can correctly deduce how the killer chooses his victims. Mu-chi succeeds and the kidnapper refuses to let the child go. All the evidence suggests he kills him. His body is found a year later.
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    • Hyun-su and her brother are kidnapped and driven far away from their home. They manage to escape and end up lost in the forest, late at night, with no food and nothing to keep them warm, and no way of getting help.
    • Bong-yi learns that Yo-han was the father of Hong-ju's baby, so she confronts Hong-ju and threatens her child's life.
    • Jae-hoon's brother dies when he's trapped in a burning house.
  • A God Am I: As a child Jae-hoon tells a crucifix that God has no right to be a deity so Jae-hoon is replacing him. As an adult he writes "I am the Almighty" at the scene of Mu-won's murder.
  • A Minor Kidroduction:
    • Mu-chi and Mu-won first appear as little boys who witness their mother's murder.
    • Jae-hoon first appears as a child who's already showing signs of becoming a serial killer.
  • Amusement Park of Doom:
    • Daniel Lee apparently gets killed in an amusement park. Played with since the park itself isn't creepy, but the serial killer chooses it to commit another murder.
    • A serial killer kidnaps a child at an amusement park.
  • And I Must Scream: Seo-joon harvested Yo-han's brain while Yo-Han was still alive.
  • An Axe to Grind: Jae-hoon kills some of his victims with an axe.
  • Asshole Victim: All of Ba-reum's victims after he develops amnesia. Deuk-soo is a rapist and child molester, Jae-shik is a rapist, and Byung-tae murdered a child.
  • The Atoner: Ba-reum becomes this after regaining his memories of being a serial killer. Before his death he asks Mu-chi to use his assets to help his victim's families.
  • Bad People Abuse Animals:
    • Jae-hoon kills a rabbit, his father's dog, and his father's pet fish. The creepiest part? He's a child when he does this!
    • Ba-reum snaps a bird's neck and kills two cats when Yo-han's personality takes over — or rather when Ba-reum's original personality takes over.
    • A victim's dog finds their owner dead, so the murderer kills the dog too.
  • Bare-Handed Blade Block: Bong-yi grabs the killer's knife as he's about to stab her. Reality Ensues because this cuts her hands badly.
  • Bittersweet Ending: Ba-reum dies, but Seo-joon is finally dead, Yo-han's name has been cleared, and Mu-chi, Bong-yi and Hong-ju can carry on with their lives.
  • Blasphemous Boast: Jae-hoon writes "I am the Almighty" at the scene of a murder.
  • Brain in a Jar: Ba-reum investigates Seo-joon's laboratory and finds human brains still preserved in jars.
  • Brain Transplant: Seo-joon transplants part of Yo-han's brain into Ba-reum's brain.
  • Cowboy Cop: Mu-chi will go to any lengths necessary to bring criminals to justice. Any lengths. Including assaulting suspects.
  • Creepy Child:
    • Jae-hoon, and how.
    • When he was a child Hyung-chul murdered his sister.
  • Criminal Mind Games: One of the serial killers leaves a message for Mu-chi then phones him after a press conference, both times to taunt him. Then he gives Mu-chi a challenge: figure out how Jae-hoon chooses his victims, and the child he's kidnapped will be released. Fail, and the child will die. Mu-chi answers the question correctly... and is rewarded by seeing his brother murdered on live TV. And Jae-hoon kills the child anyway.
  • Death of a Child:
    • Su-jin is just a child when her brother murders her.
    • Min-ji was only six when Byung-tae murdered her.
    • Han Kook is found dead a year after he was kidnapped.
    • Jae-hoon's brother dies when their house is set on fire.
  • Death Seeker: Ji-eun becomes one when she learns her unborn baby is a psychopath. She asks her attacker to kill her, and when she's rescued she yells at her rescuer that he should have let her die.
  • Distant Prologue: Different parts of the first episode take place twenty-five, twenty and fifteen years before the rest of the series.
  • Drop the Hammer:
    • The Head Hunter uses a hammer to kill one of his victims.
    • Yo-han almost kills Ba-reum with a hammer.
  • Eat the Evidence: Done accidentally when a police officer prepares coffee, unaware the coffee stick is evidence found at one of the murder scenes.
  • Evil All Along / The Killer in Me: Ba-reum is a serial killer. His change in personality is because of his Laser-Guided Amnesia and because he had part of Yo-han's brain added to his own.
  • Face Death with Dignity: Mu-won's last words to his murderer.
    Mu-won: May the Lord save your soul.
  • Finally Found the Body: Han Kook's body is found a year after his disappearance.
  • Fingore: Ba-reum cut off Chi-guk's finger.
  • Forced to Watch: Mu-chi is forced to watch as Mu-won is murdered on live TV.
  • Foreshadowing: Ba-reum describes the killer as a perfectionist. Later he notices a box has been moved slightly, showing he's a perfectionist too.
  • Forgotten First Meeting: Ba-reum and Yo-han met as children. Ba-reum only remembers this after Yo-han's death.
  • Good All Along: Yo-han wasn't a serial killer. He died trying to stop the real killer, Ba-reum.
  • Gory Discretion Shot: During the first on-screen murder the camera cuts away from the murder itself to focus on a terrified girl who witnesses it.
  • Harmful to Minors:
    • A young girl witnesses the first on-screen murder.
    • Later two young boys see the serial killer attack their mother. When he comes after them one of them is almost killed while the other is Forced to Watch.
    • Jae-hoon's siblings hide in terror when Jae-hoon kills their father and comes looking for them.
    • A young boy is kidnapped by a serial killer and held hostage as a decoy.
    • Ko-nam is almost killed when Byung-tae pours a chemical on his head.
  • He-Man Woman Hater: Hyung-chul kills women (including his own sister) because he hates them.
  • Heroic Sacrifice: Mu-chi's mother sees the killer about to attack her sons so she gets him to chase her instead. Sadly he goes back to the van after she's dead, leading to Mu-won performing his own (non-fatal) Heroic Sacrifice to save Mu-chi.
  • Imperiled in Pregnancy: Ji-eun is attacked and almost killed while pregnant. Unusually she deliberately put herself in danger and was trying to get killed.
  • Interrupted Suicide: Ba-reum is about to jump off a bridge when he's interrupted by his phone ringing.
  • Jekyll & Hyde: Thanks to the Brain Transplant Ba-reum now has a switch in his brain. And when it's triggered, Yo-han's personality takes over and he becomes a psychopath. Or so we're led to believe. Turns out Ba-reum's original personality is the "Hyde" and Yo-han is the "Jekyll".
  • Killer Cop: Played with. Ba-reum is a policeman and the evidence suggests he's one of the serial killers. Then we're led to believe part of a serial killer's brain was transplanted into his head... and then it's revealed the original Ba-reum was the real serial killer and Yo-han's brain is restraining him.
  • The Killer Was Left-Handed: Mu-chi deduces one of the killers is left-handed from the angle of the knife.
  • Laser-Guided Amnesia: Ba-reum develops amnesia after undergoing brain surgery. The Brain Transplant might have something to do with that.
  • Like Brother and Sister: Ba-reum tells Bong-yi he sees her a little sister when she asks if he wants to marry her.
  • Like Father, Like Son: Subverted. We're led to believe Seo-joon and his son Yo-han are both murderers. Then it turns out Yo-han was innocent. Then double subverted when it's revealed Yo-han isn't really Seo-joon's son. Ba-reum is, and he did become a murderer like his father.
  • Long-Lost Relative: Michaela, the girl at the orphanage, is really Jae-hoon/Ba-reum's sister Jae-hee.
  • Mad Doctor:
    • Seo-joon is a brain surgeon who's also a serial killer and experimenting on his victim's brains.
    • Seo-joon's colleague, Daniel Lee, follows in his footsteps and encourages Ba-reum to kill people.
  • Mama Bear: Mu-chi's mother lures the killer away from her children, then clings to his leg in a desperate attempt to stop him going back.
  • Man Bites Man: Ba-reum bites Deok-soo before killing him.
  • Miles to Go Before I Sleep: Ba-reum plans to commit suicide, but first he wants to clear Yo-han's name and catch Chi-guk's murderers.
  • Mistaken for Murderer: Ba-reum stops Bong-yi late at night while wearing blood-covered clothes. Bong-yi and her grandmother get the wrong idea and freak out. Played with when it turns out he really is a murderer.
  • My God, What Have I Done?: Ba-reum has this reaction when he regains his memories of being a serial killer.
  • Nice Guy: Ba-reum helps elderly people with their laundry, feeds stray cats, and jumps in front of a car to save a bird. Though this leads to people wondering if he's too nice to be genuine. They're right.
  • Offing the Offspring:
    • Almost happens when Jae-hoon's mother tries to strangle him while screaming she never should have given birth to him, then averted when he survives.
    • Ji-eun tells Seo-joon she killed their son as soon as he was born. She lied. Their son, Sung Yo-han, is alive and well... until Seo-joon kills him.
  • Off with His Head!: The Head Hunter cuts off his victims' heads.
  • Ominous Korean Chanting: Shows up on the soundtrack occasionally.
  • Once More, with Clarity!:
    • The end of episode four shows Ba-reum approaching Han Kook, giving the impression he's the kidnapper. The next episode reveals it's not really Han Kook but a decoy cast by Mu-chi, leaving it ambiguous if Ba-reum is the killer or not. He is.
    • Early in the series Ba-reum runs out in front of Mu-chi's car to save a bird. Later it's revealed Ba-reum set up this incident to make himself look good.
    • Yo-han attacks Ba-reum, leading to both of them being seriously injured. It turns out Yo-han figured out Ba-reum was the killer and was trying to stop him.
    • Episode one shows Jae-hoon standing over his father's body, implying he killed him. Episode eighteen reveals his father died accidentally during a fight with Su-ho.
  • Outliving One's Offspring:
    • Ji-eun and Seo-joon outlive their son Yo-han, who is killed by Seo-joon. Then subverted with the reveal Yo-han wasn't their son.
    • Hyung-chul's parents outlive their daughter Su-jin, who's murdered by Hyung-chul.
    • Chi-guk's mother outlives him.
  • Parasol of Pain: Bong-yi's grandmother beats Ba-reum with an umbrella when she mistakenly thinks he's about to kill Bong-yi.
  • Parting Words Regret: Bong-yi regrets the argument she had with her grandmother after her grandmother's murder.
  • Patricide:
    • Jae-hoon stabs his father to death. Subverted when it's revealed he didn't kill his father after all.
    • Ba-reum kills his father Seo-joon.
  • Pay Evil unto Evil: Ba-reum decides to do this when he realises he has to kill someone. So he chooses rapists like Deok-soo and Jae-shik to be his victims.
  • Please Wake Up: After Chi-guk's death Ba-reum begs him to wake up.
  • Rage Against the Heavens: Jae-hoon asked God to stop him becoming a monster. It didn't work, so when he becomes a serial killer he chooses victims associated with the seven deadly sins and arranges their bodies so they're pointing their middle finger towards a cross.
  • Rape as Backstory: Bong-yi was kidnapped and raped when she was a child.
  • Redemption Equals Death: Ba-reum tries to make amends as the Brain Transplant slowly kills him. He dies after finally killing Seo-joon.
  • Red Herring: Everything suggests Yo-han is the killer... until he dies and the murders continue. Then it's revealed Yo-han was Good All Along and Ba-reum is the real killer.
  • Revenge: Mu-chi's motivation. He wants to get into a detention centre and kill his parents' murderer.
  • Serial Killer:
    • Episode one revolves around the hunt for a serial killer nicknamed the Head Hunter, real name Dr. Han Seo-joon, who's killed at least twenty people.
    • Twenty-five years later Jae-hoon, now known as Ba-reum, has become another serial killer. And so has Hyung-chul.
  • Scars Are Forever: Bong-yi cuts Ba-reum's arm when he tries to kill her. Over a year later the scar hasn't faded, allowing her to recognise him when she sees it.
  • Shadow Discretion Shot: The attempted murder of Mu-won is shown by the killer's shadow hitting him (off-screen) a hammer.
  • Shipper on Deck: Bong-yi's grandmother ships Bong-yi and Ba-reum.
  • Snow Means Death: The first on-screen murders happen while it's snowing heavily.
  • Someone to Remember Him By: Hong-ju was pregnant with Yo-han's child when Yo-han died.
  • Switched at Birth: Ba-reum and Yo-han. Ba-reum is Seo-joon's son, not Yo-han.
  • Theme Serial Killer: Jae-hoon chooses his victims to act out fairy-tales associated with the seven deadly sins.
  • Troubling Unchildlike Behaviour:
    • The series starts with Jae-hoon setting a rat loose in a snake's cage and watching the snake hunt it down.
    • After witnessing his mother's murder and his brother's attempted murder, Mu-chi gets a knife and attacks the murderer.
    • Jae-hoon cuts open a rabbit to see if it's pregnant. He also scratches his own arm because he's annoyed with the other children but can't take it out on them, so he takes it out on himself. Then he pours ammonia into a fish tank to kill all the fish. Then he drowns his father's dog. And at the end of episode one he kills his father.
    • Hyung-chul is a child when he kills his younger sister and his mother.
  • Utopia Justifies the Means: Young-shin wants to create a utopia without any psychopaths. To do this she uses Jae-hoon's murders and the OZ organisation to gain support for her bill, which if passed will mean all unborn babies with the psychopath gene will be aborted.
  • Vomit Discretion Shot: Ba-reum vomits off-screen after seeing a cat's mutilated body.
  • Vorpal Pillow: Bong-yi suffocates Yo-han with a pillow. Justified since he's unconscious and seriously injured. Then subverted when it turns out she didn't kill him. Seo-joon killed him by transplanting part of his brain into Ba-reum's.
  • Wham Line:
    • Bong-yi's line "He wasn't a lefty. He was definitely a righty." This confirms there's more than one serial killer on the loose, since the one who attacked Ba-reum was left-handed.
    • Ba-reum's line at the end of episode fourteen. "It was me. It wasn't Sung Yo-han. It was me."
  • Wham Shot:
    • At the end of episode four Ba-reum walks into the room where Han Kook is a prisoner.
    • The end of episode sixteen reveals Su-ho killed Ba-reum's mother.
  • "Where Are They Now?" Epilogue: The epilogue takes place three years after the main series. Young-shin is pardoned but implicitly killed after her release, Mu-chi and Bong-yi are still friends, and Ba-reum died in prison and Mu-chi visits his grave.
  • Would Hurt a Child:
    • The Head Hunter attacks and almost kills a young boy.
    • One of the serial killers kidnaps a child and threatens to kill him unless Mu-chi can answer a question.
    • Byung-tae murders one child and attempts to murder another.
  • Your Days Are Numbered: The Brain Transplant is slowly killing Ba-reum.


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