Exams, Secrets, and a Chilling Warning

Episode 5 of Undercover High School takes us deeper into the mystery as Hae-seong juggles exams, suspicions, and a cryptic warning that sends chills down his spine. With a shocking discovery at the end, this episode delivers suspense, emotional depth, and unexpected connections. Let’s break it down!

Surprise in the Closet and a Quick Escape

The episode flashes back to where we left off—Soo-a catching Hae-seong’s team tumbling out of his closet. Thinking fast, they pretend to be his part-time colleagues, claiming they were trying to surprise him. When Soo-a remains skeptical, Hae-seong fakes fainting, and his team ‘rushes’ him to the hospital, narrowly escaping exposure.

In the present, Seok-ho, Mi-jung, and Young-hoon are all nervously hoping Hae-seong scores well on his midterms. Meanwhile, Young-hoon is still dazed over his accidental kiss with Mi-jung. He confesses his feelings, but Mi-jung brushes him off, much to his disappointment.

Over dinner, Seok-ho warns Hae-seong about Soo-a’s growing suspicions, while Hae-seong himself is distracted—by thoughts of his kiss with Soo-a. Turns out, she might be onto something big.

Soo-a’s Growing Suspicions

Soo-a isn’t convinced Hae-seong is a real high schooler. While leaving his building, she noticed his phone number on a car! Over drinks with her colleague Ri-an, she shares her suspicions—only for her mother to overhear. Later that night, a very drunk Soo-a stumbles not into her own home, but into Hae-seong’s. In a hilarious moment, he tries disguising his voice over the intercom, but thankfully, her mother arrives just in time to take her home. That’s when Hae-seong realizes—they’re next-door neighbors.

Midterms and Rising Tensions

The next day, the midterm results are out. Hae-seong lands in 10th place, securing his eligibility for the student council. Meanwhile, Yoo-jung takes first place for the first time, dethroning Ye-na. Though Ye-na puts on a friendly front, the jealousy in her eyes says it all.

Elsewhere, Chairwoman Myeong-ju meets with Chief Editor Yoon from Seojin Daily, offering him whatever he wants in exchange for writing a piece about her vision for global privatized education. Yoon, unimpressed by bribery, walks away. Later, Principal Park informs Myeong-ju about Ye-na’s ranking slip, and soon, Ye-na receives a summons to her mother’s office, looking terrified.

Getting Into the Student Council

Hae-seong tells his team that his student council application is in—but he has competition. In a hilariously awkward attempt to win Ye-na’s favor, he pulls out old-fashioned flirting moves. Thankfully, he’s chosen anyway, saving him further embarrassment.

Meanwhile, Soo-a attempts to verify Hae-seong’s school records. The listed number redirects to his undercover team, who cover for him smoothly. When Hae-seong arrives at the staff room looking for the student council room key, he catches her investigating him.

Elsewhere, Yoo-jung still refuses to talk to him, leaving Hae-seong confused. Ye-na, however, spies on their interaction, growing increasingly suspicious.

Secrets of the Grandfather Clock

At his first student council meeting, Hae-seong stays behind to examine the grandfather clock but is interrupted by Ye-na and Yoo-jung. Ye-na invites them both to dinner, hinting at something important to discuss.

Meanwhile, Soo-a is still watching Hae-seong—literally. Ri-an, visiting the sandwich shop (aka the team’s secret HQ), sends a live feed to Soo-a in hopes of catching something suspicious. But the team expertly maintains their cover. Frustrated, Soo-a receives even more paperwork from Vice Principal Baek, keeping her occupied.

A Tense Dinner and a Painful Truth

At dinner, Ye-na’s true colors shine as she treats Yoo-jung like a servant, ordering her around. Hae-seong, unable to hold back, calls her out and even pays the bill to shut things down. After Ye-na leaves, he confronts Yoo-jung, finally realizing this is why she didn’t want him to join the council. But she tearfully insists she wants things to stay the same and begs him not to interfere.

Back home, Ye-na is furious. We learn that her mother—Chairwoman Myeong-ju—ordered her to let Hae-seong onto the student council. What is Myeong-ju up to?

A Chilling Warning

Late at night, Hae-seong sneaks back into the school and unlocks the grandfather clock. But to his surprise—it appears empty. Before he can process this, someone slides a note under the door.

It reads: “Hello, Agent Jeong Hae-seong.”

Shocked, Hae-seong takes the note to Seok-ho, who brings it to Director Kim. Kim immediately orders them to investigate who sent it while secretly digging into the school staff himself. When he finally finds something, his reaction suggests it’s bad news.

A Dangerous Game

Hae-seong discovers that the CCTV footage near the student council room was deleted as part of a “server reboot.” In reality, Principal Park wiped the footage under Myeong-ju’s orders. However, even they don’t know who left Hae-seong that note.

Meanwhile, Soo-a’s colleague Joon-ho helps her with the extra reports, and while flipping through an old book, she stumbles upon something shocking—the 2003 student council member list.

A Terrifying Fall and a Familiar Notebook

Hae-seong gets a call from an anonymous number—it’s the school’s security guard, the same man he caught sneaking into the basement episodes ago. He’s the one who slipped him the note, and he urgently tells Hae-seong to meet him on the rooftop.

As Hae-seong approaches, the grandfather clock suddenly chimes. He remembers Dong-min’s story: “Crimson eyes will come for you.” Before he can enter the school, a body plummets from the rooftop—it’s the security guard.

His eyes are eerily red. Clutched in his hand is a small black notebook covered in stars.

A flashback reveals that this is the same notebook little Hae-seong gave his father years ago.

Soo-a’s Shocking Discovery

The episode closes with another flashback: Si-hyun (young Hae-seong) and his father having dinner with a young girl—Bong-ja, the girl who would later become Soo-a.

Back in the present, Soo-a flips through the 2003 student council book and finds something that leaves her speechless—

A photo of Si-hyun’s father standing alongside the student council members.

A Deadly Secret, Unexpected Confessions, and a Game-Changing Revelation

Episode 6 of Undercover High School is packed with shocking discoveries, intense confrontations, and growing romantic tension. As Hae-seong gets closer to uncovering the truth about his father, new threats emerge, and old connections resurface in surprising ways. Let’s break it all down!

A Murder on the Rooftop

The episode opens with the school’s security guard, Kim Hyeon-ho, waiting on the rooftop with a mysterious notebook—none other than Hae-seong’s father’s. But before Hae-seong can arrive, a masked man attacks him, trying to steal the notebook. In the struggle, Hyeon-ho falls to his death.

Hae-seong arrives moments too late, finding his lifeless body and the notebook. He spots the masked man fleeing and chases him to the rooftop, leading to a tense fight. But the man manages to escape when a sudden noise distracts Hae-seong.

As the masked man disappears into the night, he removes his mask—revealing himself as Principal Park. He gets into a car with Chairwoman Myeong-ju, setting the stage for a deeper conspiracy.

The Truth About Hae-seong’s Father

Furious and desperate for answers, Hae-seong storms into Director Kim’s office, demanding to know why his father’s notebook was found at the school. Director Kim finally confesses—Jeong Jae-hyeon’s last mission was the same as Hae-seong’s. The revelation devastates Hae-seong, who realizes the NIS always knew where his father disappeared.

Overwhelmed, he nearly punches Director Kim, but Seok-ho intervenes just in time. Feeling betrayed, Hae-seong takes a break from the mission and stops attending school, choosing instead to go through his father’s old notes.

A ‘Suicide’ and Growing Tensions

The next morning, the entire school is shaken by the security guard’s death. The official story? Suicide. The school claims to have found a death note in his office, but Hae-seong knows better.

Meanwhile, in the student council room, Ye-na corners Yoo-jung, demanding to know if she has feelings for Hae-seong. Yoo-jung denies it, prompting Ye-na to declare that she will pursue him instead.

Back at the NIS, Director Kim’s subordinate asks him if Seok-ho was aware of Jae-hyeon’s mission. Kim makes a cryptic comment about Seok-ho’s secrets, and later, Seok-ho is seen looking at an old photograph of himself, Jae-hyeon, and Director Kim. What is he hiding?

Returning to the Mission

After struggling on his own, Hae-seong finally returns to his team, determined to finish what his father started. He tells everyone at school that he was dealing with a personal matter, though Soo-a seems more annoyed than usual at his sudden return.

Back in the student council room, Hae-seong revisits the grandfather clock. Using his father’s notes, he deciphers the horror story associated with it—an upside-down corpse. Following the clue, he turns the clock’s hands to 6:30 (the reverse of midnight, when it chimes). The clock begins to play a tune, which he records on his phone.

Soo-a’s Ultimatum

Before he can investigate further, Soo-a enters the room. She directly confronts him about Kim Hyeon-ho’s death, accusing him of knowing the truth. A flashback reveals that she was at the school that night and saw everything—including Hae-seong pulling a gun on the masked man.

At present, Soo-a boldly declares that she knows he isn’t a student. Left with no choice, Hae-seong confesses—he’s an NIS agent. He gives her two options: cooperate with the NIS or risk jail time for leaking classified information.He gives her one day to decide.

A Mysterious Tune and an Apology

Hae-seong’s team deciphers the tune from the grandfather clock—it’s the school’s anthem, composed by Seo Byeong-mun. The next clue is linked to the third ghost story, about a piano that plays by itself. But before they can investigate, they turn their attention to Soo-a.

Seok-ho is furious that Hae-seong threatened an innocent civilian and orders him to apologize immediately. That evening, Hae-seong shows up at Soo-a’s mother’s diner, sincerely apologizing and begging her to keep his secret. To his surprise, Soo-a agrees to help him—though she briefly imagines herself being rewarded with a presidential citation and a full-time job.

Later, as they walk together, Hae-seong reveals that Yoo-jung is his little sister. He takes her hand and promises to protect her, sending Soo-a into a fluster.

The Conspiracy Deepens

Elsewhere, Myeong-ju meets with a shadowy figure, who reprimands her for how she handled Kim Hyeon-ho. A flashback reveals that Kim Hyeon-ho used to be an NIS agent, and he had planned to hand over Jae-hyeon’s notebook to Hae-seong. He also accused Myeong-ju of working with a mole inside the NIS—someone after the gold.

At present, Myeong-ju speaks with the mole, who warns her to avoid further murders. But she ominously reminds him that he would have been in danger if Hae-seong had met Kim Hyeon-ho.

The Haunted Piano and A Childhood Revelation

Hae-seong investigates the next ghost story—a piano that plays by itself. The legend tells of a piano club president who abandoned a girl when she got pregnant. Heartbroken, she took her own life, and ever since, the piano has played by itself.

Soo-a screams upon reading the story, recalling that she saw a grand piano in Myeong-ju’s office. However, the only way to access it is during a school event called Night for Byeongmunites. There’s just one problem—Hae-seong can’t attend because of his demerit points.

A Hilarious Contest and Hidden Scars

Soo-a comes up with a solution—Hae-seong should compete in a contest to become the face of Byeongmun High,which would grant him merit points.

At the contest, Hae-seong is hilariously terrible at posing for photographs, but with Soo-a’s guidance, he suddenly nails it. Meanwhile, Ye-na gets agitated when asked to roll up her sleeve for a photo. Yoo-jung quickly makes an excuse for her and pulls her away.

A flashback shows Yoo-jung discovering scars on Ye-na’s wrist. In the present, when Yoo-jung expresses concern, Ye-na lashes out, leading Hae-seong to step in. Misunderstanding his actions, Ye-na assumes he and Yoo-jung are dating and runs away in tears. Yoo-jung, however, is furious at Hae-seong for interfering.

Later, Soo-a advises Hae-seong to let Yoo-jung come to him when she’s ready. Soo-a then says something that sparks a memory in Hae-seong—something Bong-ja, his childhood friend, once said.

A Shocking Realization

As they leave the diner, Soo-a’s mother calls out to her by her childhood name—Bong-ja. Hae-seong freezes as he realizes who she is.

Finding His Father’s Trail

The episode ends with Hae-seong exploring the abandoned school basement, now covered in investigation papers. Using his father’s notebook, he identifies it as Jae-hyeon’s old hideout.

Standing in the darkness, he whispers: “I’ll find you soon, Dad.”

DramaZen's Opinion

Twists, Tensions, and Game-Changing Reveals!

Episodes 5 and 6 of Undercover High School delivered everything—mystery, action, emotional depth, and even some unexpected romance! Hae-seong is finally uncovering the truth about his father’s mission, but every answer leads to even more dangerous questions.

Episode 5 had me on edge with the mysterious note, the security guard’s eerie death, and Soo-a’s shocking discoveryabout Hae-seong’s real identity. The pacing was perfect, balancing suspense with the ongoing school politics, like Ye-na’s jealousy over Yoo-jung. And that final reveal—Soo-a’s childhood connection to Hae-seong? Chef’s kiss!

Then Episode 6 took things up a notch with Hae-seong confronting Director Kim, the masked man’s true identity, and the discovery of his father’s old hideout. Plus, the slow-burn chemistry between Hae-seong and Soo-a? Absolutely electric! I loved seeing her flustered reactions, especially after realizing she was Bong-ja all along.

With an NIS mole, Myeong-ju’s secret agenda, and Hae-seong getting closer to the truth, the stakes have never been higher. I need Episode 7 ASAP!