Undercover High School Episode 7 Recap: Shocking Revelations

In the latest episode of MBC's drama Undercover High School (언더커버 하이스쿨), Sung Kang-joon (서강준) and Jin Ki-joo (진기주) embark on a quest to uncover the truth behind a third urban legend, leading to unexpected revelations. The episode, which aired on March 15, 2025, achieved a nationwide rating of 6.8% according to Nielsen Korea, with a notable spike to 8.6% during a pivotal epilogue scene where Kang-joon’s character reveals his real name, Jung Si-hyun (정시현), to his father. The 2049 demographic rating also reached 2.4%, indicating strong interest from younger viewers.

In this episode, Kang-joon discovers that Ki-joo is his first love, Oh Bong-ja (오봉자), which brings a smile to his face as he reminisces about their childhood. Ki-joo, on the other hand, hints at their shared past while talking to a colleague, igniting a budding romance between the two.

Meanwhile, agents from the National Intelligence Service's Domestic Team 4 uncover that a school anthem recorded in a grandfather clock was performed by a four-hands ensemble. To gather clues about the urban legend, the two must perform the anthem together, prompting Ki-joo to join the investigation. Their collaboration leads to a successful acquisition of the principal's fingerprint, necessary to bypass the security system of the chairman's office.

The chemistry between Kang-joon and Ki-joo creates heart-fluttering moments, as he fumbles on the piano keys while trying to impress her and finds himself in an awkward situation during a practice session. His comedic attempt to regain composure after a back hug adds a humorous touch to the episode.

As the highly anticipated 'Night of the Patient' event unfolds, disguised agent Go Young-hoon (조복래) sabotages the power supply while the parents are gathered separately. In the dark, Kang-joon and Ki-joo attempt to reach the chairman's office, but the power is restored sooner than expected, putting their plan at risk. To buy them time, Park Mi-jung (윤가이) and Young-hoon engage in a hilarious act, even sharing a kiss to distract the security personnel.

Thanks to their antics, Kang-joon and Ki-joo manage to reach the chairman's office, but they soon find themselves in a physical confrontation with security guards. Having trained for such scenarios, the duo successfully overpowers the guards, providing a satisfying climax to their efforts.

Towards the end of the episode, Kang-joon confronts a shocking truth. After failing to perform the anthem due to a keyboard mishap, they decide to leave the chairman's office in haste. While deleting access logs from Myung-joo's (명주) computer, he stumbles upon a file titled 'Operation Plan_Undercover High School,' which contains details about the event and his personnel record, sending chills down his spine. The revelation that Myung-joo knows everything raises questions about their future confrontations.

Episode 7 captivated viewers with a mix of romantic moments and thrilling investigations, keeping audiences on the edge of their seats. The plot twists and turns have heightened anticipation for the next episode.