Seo Kang-joon Stars in ‘Undercover High School’ Kdrama

Looking for your next Kdrama addiction? The action-packed Viu Originals’ hit, Undercover High School (언더커버하이스쿨, 臥底高中), offers just the right mix of gripping suspense, heartfelt teen dilemmas, and hilarious comedic moments to keep every fan glued to the screen. Powered by Seo Kang-joon’s charismatic presence, alongside stellar performances by Jin Ki-joo and Kim Shin-rok, this show has quickly become one of the most eagerly anticipated Korean dramas of 2025. If you’ve been searching for good Korean series to watch, look no further—you’ve just found your new favorite TV show streaming exclusively on Viu.

Introducing ‘Undercover High School’: A Spy Agent’s Secret Identity Unveiled

At first glance, Jeong Hae-seong (Seo Kang-joon) seems like your typical charming new transfer student who effortlessly draws attention at Byeongmun High School. With movie-star good looks, an inviting smile, and irresistible charm, he’s instantly popular with peers and teachers alike. But behind this seemingly perfect high-schooler persona, there’s a startling twist—Hae-seong isn’t actually a student at all. He’s an elite national agent from South Korea’s National Intelligence Service (NIS), sent on an undercover mission to retrieve Emperor Gojong’s hidden treasure.

However, what initially seems like a straightforward treasure hunt quickly spirals into something much deeper. Beneath the polished hallways and bright classrooms of Byeongmun High lies a tangled web of corruption, injustice, and greed. As Hae-seong’s undercover mission takes dangerous turns, he’s forced into confronting dark truths about wealth, power, and obsession ingrained within the school’s privileged society.

Yet, amid bouts of thrilling action sequences and investigative intensity, Hae-seong forms genuine friendships, finds heartfelt mentorship, and learns valuable life lessons about loyalty and courage. Balancing thrilling suspense with teen drama and comedy, Undercover High School brilliantly captures the heart and humor audiences love about Korean TV shows.

Meet Your Favorite Korean Drama Stars: Seo Kang-joon, Jin Ki-joo & Kim Shin-rok

A Kdrama is truly special when its cast shines brightly through every intense scene and comedic plot twist. Undercover High School proudly showcases a cast of remarkable talents—highlighting exactly why viewers regularly call it one of the best Korean TV series of the year.

Seo Kang-joon stars as Jeong Hae-seong, delivering another exceptional performance full of charisma, humor, and impressive action scenes. Known widely for his previous memorable roles, Seo Kang-joon easily balances comedic timing with emotional depth, making this undercover agent a truly relatable character.

Opposite Seo, Jin Ki-joo brilliantly portrays Oh Su-a, a dedicated history teacher nurturing students’ dreams at Byeongmun High School. Warm yet authoritative, Su-a’s complicated past slowly comes back to haunt her when her mysterious student stirs long-held memories. Her chemistry with Hae-seong becomes rooting-worthy and heartfelt—a huge plus for fans seeking romantic subtlety in good Korean dramas.

Kim Shin-rok takes on the powerful, enigmatic Seo Myeong-ju, the driven Chairwoman of Byeongmun High. Her compelling portrayal of a deeply flawed, manipulative character injects dramatic tension into the story. Alongside rising star Kim Min-ju as student council president Lee Ye-na, the series captures multiple layers of intrigue, friendship, and ambition.

Episode 8 Recap — “The Plan for VIP Students”: Twists, Turns & Secrets Exposed

Released on March 15, 2025 on Viu, the gripping eighth episode highlights major turning points and startling reveals that captivated viewers. Jeong Hae-seong discovers troubling evidence pointing toward a potential traitor within the NIS ranks. This revelation shakes him to the core, causing him to doubt the integrity of his mission and the people around him.

Meanwhile, Oh Su-a learns of a covert operation within Byeongmun High itself. She exposes a shocking scheme designed to artificially guarantee elite results exclusively to privileged VIP students. As the layers continue to peel back, the audience witnesses how deeply corruption has penetrated this seemingly prestigious institution.

As the plot thickens, Jeong Hae-seong finally connects the dots between the missing historical gold and Chairwoman Seo’s sinister objectives. Realizing the stakes are higher than ever, he vows to dismantle her malicious plans, setting up the series perfectly for thrilling climactic showdowns.

Fan Reviews Are In—And They Are Loving This Drama!

Fans across the globe have expressed their praise for Undercover High School, awarding it enthusiastic ratings such as an impressive 8.8/10 on IMDb and a remarkable 97% approval rating among Google users. Admirers highlight the drama’s powerful storytelling, charismatic cast, striking cinematography, meaningful themes of overcoming school bullying, and perfect blend of action, romance, and humor.

One enthusiastic viewer commented, “Just finished watching Episode 8. It’s getting better and better! Intense yet fun, exploring meaningful themes like school bullying. Definitely recommended!”

Others rave about the lead and cast performances:

“I started because of Seo Kang-joon, but I stayed because of the storyline. Easy-to-follow, fun, and touching—it’s becoming one of my favorite Korean dramas.”

“Pure fun to watch, great action scenes, lots of laughs, and an interesting plot. Highly recommended if you’re seeking the best Korean shows!”

Another fan notes, “I love this drama so much. The story keeps me curious and interested all the way—definitely the best upcoming drama of 2025!”

Undercover High School Exclusive Wallpapers for Fans!

Fans, we have a wonderful gift for your mobile and desktop screens! We’re giving Viu users who adore Undercover High School the chance to access exclusive HD wallpapers. Featuring your favorite stars Seo Kang-joon and Jin Ki-joo, these high-quality images help you keep the excitement alive every day. Available exclusively on Viu, these wallpapers are the perfect way to show your love for this fantastic Kdrama—don’t miss out!

Frequently Asked Questions about Undercover High School:

Where can I watch Undercover High School Kdrama? You can stream every exciting episode exclusively on Viu.

What is the release date of Undercover High School? This popular Viu Original Kdrama premiered on February 21, 2025.

What is the schedule of Undercover High School? Catch new episodes of Undercover High School streaming every Friday and Saturday, exclusively available on Viu.

What genre is Undercover High School? It’s a perfect blend of Action, Comedy, Rom-com, Spy Fiction, and Teen Drama genres.

Ready to Enter Byeongmun High?

Undercover High School is becoming one of this year’s most popular Korean dramas for great reasons: its addictive storyline, brilliant ensemble cast, hilarious comedy moments, and thrilling spy action scenes. No wonder it’s already among the Korean top TV series being discussed by fans everywhere.

Ready to join Jeong Hae-seong’s mission? Visit Viu.com to sign up and watch Undercover High School now!

Don’t miss the exclusive Undercover High School wallpapers offered only for fans who stream via Viu. Sign up and get your exclusive HD wallpaper today!