In Episode 9 of Teach You A Lesson, we take a look at a different side of school violence – manipulation, exploitation and emotional abuse, not physical attacks. Instead, the story belongs to Gyu-cheol, whose final moments we are left shocked by and where the direction of the story is completely changed, even as the ERPB successfully exposes a hidden bullying case.## Public Criticism of Jinwon High School
The episode starts with angry protestors gathering outside of Jinwon High School. Parents and members of the public are furious that convicted criminal Gyu-cheol has been allowed to return as a student. Despite mounting criticism government officials are still refusing to answer questions about his release.
The tension rises as Hwa-jin meets with Gyu-cheol, making it clear that their relationship is strictly professional. As an ERPB official, he will monitor Gyu-cheol’s behavior and determine if he can safely return to school life.
Inside the school, Gyu-cheol is an outcast from day one. His fellow students constantly remind him, calling him a murderer, refusing to accept him as one of their own.# Hidden Bullying Case Revealed
Surprisingly, Gyu-cheol reports the bullying incident to the ERPB. Han-rim is suspicious of his motives but the complaint gets Hwa-jin’s attention.
The supposed victim is shy student Jang Seong-gu who says nothing is wrong when asked. But soon enough, Hwa-jin begins to notice some strange behavior from Seong-gu’s friends, who use his mobile hotspot and Wi-Fi as if there were no cost to him at all.
Further investigation reveals a much darker picture. Lee Chi-ho drags classmates to use Seong-gu. They are not only stealing his money but they are also using his online accounts to con unsuspecting victims.
Things go south when one of the scam victims accidentally attacks Seong-gu, believing he’s the one behind the fraud.# School Violence Committee Lets Victim Down
Gyu-cheol encourages Seong-gu, and he finally decides to tell the truth about what has been happening. Unfortunately, the school system turns against him at once.
Chi-ho is the first to complain, saying that Seong-gu is bullying him. When the case reaches the school violence committee, Seong-gu suddenly finds himself as the aggressor, not the victim.
He attempts to tell the committee the truth, but they ignore him, demanding proof. Chi-ho has a number of public supporters, and his lawyer says Seong-gu can settle the matter if he just apologizes.
The hearing brings out one of the episode’s most powerful themes: the way institutional failures can protect bullies and punish the victim.## Han-rim Goes Underground
The ERPB goes undercover and is determined to get to the bottom of it. Han-rim goes back to high school undercover, and gains Chi-ho’s confidence.
Disguised as a friendly classmate, she gives Chi-ho and his friends access to her social media accounts and Wi-Fi network. The group jumps at the chance without knowing Han-rim has already laid a trap.
Han-rim gives Geun-de access to their devices and Geun-de uses it to run the same scams and harassment the students had previously inflicted on Seong-gu.
Chi-ho finally breaks his cool and attacks, after having seen the results firsthand. ### How the ERPB Altered the Script
When Chi-ho challenges Han-rim aggressively, she promptly reports him for harassment. But this time, the investigation will be very different.
Hwa-jin arrives with evidence and systematically tears down Chi-ho’s defense. Hwa-jin reminds Chi-ho that he used the same tricks to frame Seong-gu as he insists he is innocent.
The truth is revealed when Han-rim discloses herself as an undercover ERPB inspector.
It’s most satisfying to watch Hwa-jin tear apart the crooked school violence committee, exposing the cracks that allowed the injustice to happen in the first place.
Seong-gu has finally been cleared of all charges, and both he and his mother thank the ERPB for restoring his reputation.# The True Intent of Gyu-cheol Revealed
Just when it seems as if the case is solved, the episode throws a devastating curveball.
Chi-ho confronts Gyu-cheol, calling him a traitor. Flashbacks show that earlier in the story, Gyu-cheol had secretly encouraged Chi-ho to bring charges against Seong-gu.
During the fight, Gyu-cheol suddenly pushes Chi-ho off the school building.
The shocking incident immediately dominates online headlines, leaving viewers wondering how far Gyu-cheol will go to achieve his goals.
Gyu-cheol visits Gi-tae the next morning, leaving behind a part of a recording where Chi-ho blames the ERPB for wrecking his life.
In that moment, Gi-tae comes to a horrible realization — Gyu-cheol has been manipulating all along. His release from prison, his cooperation with authorities, even the latest tragedy, all seem to be part of a much bigger scheme.
Gi-tae arrives at the hospital with the recording, and claims that Gang-seok and the ERPB are responsible for driving a student to attempt suicide. The episode ends with things about to blow up.## Episode 9 Recap
What makes episode 9 so special is that it addresses a kind of bullying that isn’t always recognized. It is not a story about physical violence but about social manipulation, financial exploitation and peer pressure. The investigation feels grounded and relevant, showing how easy it is to overlook victims when the evidence is hard to prove.
Han-rim is back in the spotlight. It is still one of the series’ most enjoyable assets to watch her move so easily from intrepid investigator to average student.
But the biggest takeaway is Gyu-cheol. Every episode has hinted at him being more dangerous than he seems, and Episode 9 confirms those suspicions. What he did looks like more than getting even. It looks like he had a plan and was playing games.
With only a few episodes left, the mystery surrounding Ga-yun’s death still hangs over the story. It looks like the series is saving its biggest reveals for the finale, and after this shocking ending, the battle between the ERPB and Gyu-cheol is going to be explosive.