They Tried To Bully The New Prisoner, Unaware He Would Become The Notorious Prison Boss

Recap / Main Plot

The story follows Changho, a perpetually losing lawyer married to the fierce and respected Miho, until he’s drawn into a massive conspiracy involving murder charges, stolen money, and prison power games. After Changho accidentally becomes entangled with the powerful tycoon trio—murderers who control prisons through intimidation—he’s framed, arrested, and ends up in custody after a chaotic chain of events involving hidden evidence and manipulated witness accounts.

Inside prison, Changho is believed to be the notorious underground criminal “Big Mouse.” With his reputation rising fast, he begins playing the role strategically—protecting Miho, hunting the truth about a dead professor’s research (Professor Joe/Seo), and trying to identify who truly controls everything from behind the scenes.

Over time, the “Big Mouse” identity keeps shifting between characters through betrayals, staged outcomes, poisoned deaths, and mind-games with prison leadership and corrupt hospital staff.

Standout Highlights & Notable Events

• Miho’s explosive home life and court-day pressure: She humiliates her deadbeat husband on the morning of his court date, threatens him with divorce, and later interrogates her father when she suspects betrayal.
• The mayor hires Changho for a “mouthpiece” role: The mayor’s real goal isn’t justice—it’s evidence extraction/control to break free from the tycoons’ domination.
• Prison VIP lounge infiltration: Changho distracts/records the tycoons while discovering an external accomplice, triggering a broader conspiracy about evidence and a trail involving a dashcam/USB.
• Fire extinguisher door-break rescue + dashcam truth: Changho bursts into a room during an assassination attempt, forces the victim to reveal the truth, and traces evidence back to the professor’s murder.
• Accident → “Big Mouse” identity locks in: After a drug-laced coffee (or another tainted moment), Changho spirals out of control, then “awakens” branded a genius con artist when police find drugs/gold—completely destroying his legal life.
• Prison boss arc goes feral: He escalates from powerless prisoner to feared boss, humiliating the warden with food-tray brutality and feces-bucket “discipline,” rallying followers under the Big Mouse name.
• Miho’s parallel investigation at the hospital: She uncovers corruption—DNR orders, pressured waivers for insurance payouts, and systematic medical abandonment—all tied back to the professor thesis murder cover-up.
• Fake client list twist: The mayor’s planted list and the warden’s manipulation lead to Changho winning a “names” test anyway—implying someone switched/faked everything.
• Cat-and-mouse “Big Mouse” identity reveals: Repeated attempts to pin Big Mouse fail, and the story builds toward the idea that Big Mouse may be an organization, not a single person. Major power shifts then push responsibility onto someone “behind the warden” and other coordinators.
• Election finale / radioactive water scandal: The plot pivots into a political showdown where Changho’s campaign exposes illegal chemical/radiation dumping via a fish farm—leading to electoral victory and legal consequences.
• Massive courtroom manipulation unmasked via live stream: A scripted “innocence” angle collapses when Changho’s team streams/controls the narrative, revealing actual evidence and undermining the prosecutor’s “scripted” verdicts.
• Ending arc: Corrupt figures are arrested/exposed, stolen assets are redirected (orphans/rescue organizations), and Changho’s world stabilizes—though Miho’s personal tragedy (leukemia/end-stage cancer) remains emotionally central.

Jokes / Reactions (Mostly Tone & Iconic Moments)

• Changho’s rise is sometimes treated like horror-comedy: dumping feces on the warden, smashing food trays into faces, and leveraging the fear of the “Big Mouse” myth.
• Several scenes use dark swagger around extreme cruelty, but the show’s “reaction” energy consistently flips: prison/tough guys panic whenever Changho’s reputation grows stronger.

Main Personalities / Who Appears

• Park Changho — the lawyer-turned-prison-boss “Big Mouse” target, later strategist
• Miho — nurse/wife; fierce, observant investigator; later faces leukemia
• Mayor Choi / Choy (spelling varies in subtitles: Choi, Choy) — political manipulator; key conspirator
• Jihun / Ji Hune — tycoon ally/handler; repeatedly tries to control outcomes; antagonist
• The Prison Warden — initially perceived one way, later revealed as deeply involved with hidden “dog” roles
• Three murder tycoons — imprisoned powers; try to control Changho and the evidence
• Professor Joe / Seo — murdered researcher whose thesis becomes the core “proof” object
• Jerry — Changho’s “little brother,” loyal followers; later reveals darker involvement
• Head nurse — hospital gatekeeper tied to DNR/insurance corruption and medication manipulation
• Director of hospital — supports/pushes the medical cover-up
• Duha / Cho Doha — major villain identity; manipulator who frames and escalates the conspiracy