“The Substitute”: Lies, Betrayal & Exam Pressure—Bae Hyun-sung Leads New Thriller High School K-Drama
High school K-dramas are not always about first love, friendship, and the usual growing-up struggles. Some turn school life into a tense battle for power and survival. The Substitute is the next upcoming series to watch if you enjoy stories where one wrong decision can change everything.
Starring Bae Hyun-sung, Cha Kang-yoon, and Park Yoon-ho, this TVING original places South Korea’s fiercely competitive university entrance system at the center of a crime thriller. The story begins with an unusual demand: a top student is pressured into taking an important entrance exam on someone else’s behalf.
The series has another reason to catch viewers’ attention. It is directed by Park So-yeon, who previously helmed Pyramid Game, the school thriller known for turning classroom popularity into a ruthless power struggle. Here is what to know about The Substitute before its premiere.
What Is The Substitute K-Drama About?
Titled Daerisuneung (대리수능) in Korean, the drama centers on two students whose lives look very different on the surface.
Nam Jae-yeob (Bae Hyun-sung) appears to have everything going for him. He comes from a wealthy family and has the grades and polished image expected of a successful student. However, his carefully maintained life begins to unravel as he struggles with the expectations placed on him.
Kang Geon-tae (Cha Kang-yoon), meanwhile, is a scholarship student from a financially struggling family. He consistently ranks at the top of his school and sees admission to a prestigious university as a key step toward a better future. But a decision he makes to get by leaves him vulnerable.
Jae-yeob discovers Geon-tae's weakness and uses it to pressure him into taking the university entrance exam for him. What might sound like a single dishonest arrangement becomes a dangerous situation involving personal secrets, conflicting ambitions, and consequences that could follow the students long after the exam ends.
The premise gives The Substitute a different focus from school dramas built mainly around bullying or classroom rivalries. Here, academic success itself becomes a source of pressure, and the pursuit of a better future pushes the characters towards choices they may struggle to control.
The Substitute Cast: Who Plays Whom?
The series brings together young actors in its central student roles, alongside experienced performers playing adults whose influence shapes their lives.
Bae Hyun-sung as Nam Jae-yeob: A wealthy student whose seemingly perfect image hides a more troubled side. His actions set the central conflict in motion.
Cha Kang-yoon as Kang Geon-tae: A high-achieving scholarship student whose ambition to escape poverty leaves him exposed to Jae-yeob's demands.
Park Yoon-ho as Joo Hee-dong: Geon-tae's close friend. His place in Geon-tae's life becomes more complicated when Jae-yeob enters the picture.
Uhm Ji-won as Sim Kyeong-o: A mother whose personal sacrifices are tied to her son's future.
Park Hyuk-kwon as Nam Dong-sik: Jae-yeob's father, a powerful figure whose expectations contribute to the pressure surrounding his son.
Baek Ji-won as Baek Sun-hee: Another mother whose determination to protect her son forms part of the adult side of the story.
The three student characters are especially important to the drama's setup. Their relationships are not limited to friendship or rivalry; the decisions they make could change what each of them stands to lose.
Why This School Thriller Is a Must- Watch
1. The Pyramid Game Director Is Back
Park So-yeon directed Pyramid Game, which built its suspense around a class ranking system that determined which student would become a target for bullying. The series used a familiar school setting to examine how status, group pressure, and the choices of bystanders can shape a student's life.
2. The College Entrance Exam Becomes the Source of Suspense
Many school dramas use grades and university admissions as background details. The Substitute makes the entrance exam central to its conflict.
For Geon-tae, academic achievement represents a possible route out of financial hardship. That makes the pressure placed on him particularly difficult: refusing Jae-yeob could threaten the future he has worked towards, while agreeing to the deal could put everything else at risk.
This premise gives the thriller a relatable starting point.
3. Blackmail Creates a Dangerous Power Imbalance
Jae-yeob and Geon-tae are not entering the arrangement as equals. One has discovered something he can use against the other, turning a fellow student into someone he can pressure.
That imbalance creates room for shifting loyalties and escalating conflict. Geon-tae has his own ambitions, while Jae-yeob's actions are tied to pressures in his personal life. Their competing interests make it difficult to know whether the arrangement can remain under control.
For fans of psychological school thrillers, this is one of the most intriguing parts of the setup.
The Substitute K-Drama Release Date and Where to Watch
The Substitute is scheduled to premiere on November 23, 2026, as a TVING original series in South Korea. It is directed by Park So-yeon and written by Choi Soo.
International streaming availability may vary by country. Viewers outside South Korea should check local streaming services for an official release announcement before assuming the series will be available on a particular platform.
Final Thoughts
Before its premiere, The Substitute already has a clear selling point: it turns a familiar pressure faced by students into the basis of a crime thriller. The blackmail plot, the unequal position of its two leads, and the involvement of the Pyramid Game director make it worth watching for fans of darker school dramas.
Whether it will stand alongside favourites such as Pyramid Game remains to be seen. For now, viewers who enjoy stories about ambition, secrets, and students pushed into difficult choices have another upcoming K-drama to keep on their radar.
Would you watch The Substitute for its school-thriller storyline, or does the Pyramid Game director connection make you more curious?
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