Only 2 Episodes Left… This Hit K-Drama Just Hit Rock Bottom

With only two episodes remaining, MBC’s Undercover High School is facing a steep ratings decline. According to Nielsen Korea on March 23, Episode 10—which aired the night before—dropped to a nationwide rating of 5.4%, the show’s lowest so far. In the Seoul metropolitan area, the rating was 5.3%.

This marks a significant fall from its peak during Episode 4, when the series recorded 8.3% average ratings and a momentary high of 11%. At the time, Undercover High School was one of MBC’s fastest-rising Friday-Saturday dramas. But since then, ratings have mostly stayed in the 5–6% range, trailing behind competing dramas.

🔍 Episode 10 Recap: A Gold Bar Turns Into a Grim Discovery

In the latest episode, the secret behind the much-rumored hidden gold bars was finally revealed. Seo Myeong-joo (Kim Shin-rok) returned to school and shocked viewers with her knowledge of the fourth school legend—an urban myth tied to the mystery.

Following her return, Jung Hae-seong (Seo Kang-joon) was expelled, and the NIS's Domestic Team 4 received orders to stand down and disband. Fearing for Oh Soo-ah’s (Jin Ki-joo) safety, Hae-seong remained on high alert.

The team continued to pursue the fourth legend, eventually realizing that a statue of Seo Byung-moon on school grounds might hold the key. Disguised as a deliveryman, Hae-seong snuck into school and discovered the statue could move. However, he was interrupted by Vice Principal Baek Kwang-doo (Oh Yong) and forced to flee.

Meanwhile, a photo of Hae-seong and Soo-ah appearing to be on a secret date circulated through the school, prompting the principal to suspend Soo-ah. Hae-seong intervened, publicly revealing his secret identity and resolving the misunderstanding—thanks to student Lee Ye-na (Kim Min-ju), who had discovered the truth and stepped in.

Later, Hae-seong reached the statue again, distracting Myeong-joo by falsely claiming a spy had infiltrated the school. As she hesitated, he moved the statue and descended into an underground passage—only to find not gold, but his father’s skeletal remains. A watch he had given his father as a child lay beside the body, confirming the heartbreaking truth.

The shocking discovery added emotional weight to the mystery, with Hae-seong left in tears, grappling with grief rather than the treasure he’d expected.

🌟 Seo Kang-joon’s Comeback: A Low-Key Return with High Expectations

Undercover High School marks Seo Kang-joon’s long-awaited comeback to the small screen following his military discharge in 2023. Known for his versatile performances in dramas like Are You Human Too? and Watcher, the actor returned to take on the lead role of Jung Hae-seong, a secret agent disguised as a high school teacher.

In this role, Seo delivers a blend of intensity and vulnerability—balancing action sequences with moments of emotional depth, particularly in scenes involving his late father’s mysterious past. While the drama’s ratings have seen a dip, Seo’s performance has consistently earned praise for its nuance and maturity.

Fans have also expressed excitement about his return, with many noting his more grounded, emotionally resonant portrayal compared to his past heartthrob roles. Though Undercover High School may be struggling with viewership, Seo Kang-joon’s presence alone has kept many viewers tuning in.

With just two episodes left, viewers are eager to see how Hae-seong’s character arc wraps up—and whether this drama sets the stage for even bigger roles in Seo Kang-joon’s post-military career.

🎓 What’s Next for Undercover High School?

The latest episode intensified the suspense, as characters edged closer to uncovering the truth behind the school’s fourth legend. However, the absence of the gold and the sudden appearance of Hae-seong’s father's body delivered an unexpected emotional twist that left a strong impact.

Episodes 11 and 12 (the finale) are set to air on March 28 and 29 at 9:50 PM KST. As the show nears its end, all eyes are on whether it can reverse its ratings slump and end on a high note.

📊 Undercover High School Viewership Trend (Nielsen Korea)

Episode 1: 5.6%

Episode 2: 6.6%

Episode 3: 6.6%

Episode 4: 8.3%

Episode 5: 7.2%

Episode 6: 6.7%

Episode 7: 6.8%

Episode 8: 6.1%

Episode 9: 6.1%

Episode 10: 5.4%