Some scripts grab you from the very first page. For Park Yoon Ho, that script was The Substitute, a tense crime thriller set around one of the biggest days in a Korean student’s life. With new stills out and the actor sharing his thoughts, here is everything you should know before the premiere.
What Is The Substitute About?
The drama follows three young men whose clashing desires and personal struggles push them toward an irreversible crime on the day of the college entrance exam. At its center is a top-ranking student from a low-income family who attends a prestigious private school on a special scholarship. A blackmailer who knows his secret forces him to take the exam on the blackmailer’s behalf. The exam in question is the CSAT, Korea’s national college entrance test, which shows how high the stakes are.


Park Yoon Ho’s Character: Joo Hee Dong
Park Yoon Ho plays Joo Hee Dong, an ordinary and innocent high schooler. After getting tangled in a terrible incident, Hee Dong begins to doubt the friend he trusts most. The actor describes him as an honest, completely ordinary student. Unlike his cooler, more realistic friends, Hee Dong is easily swayed by those around him because he is still young at heart.
Two Sides of Hee Dong in the Stills
The new photos show a clear shift. At first, Hee Dong beams at Kang Geon Tae (Cha Kang Yoon), the school’s top student, whom he admires and sees as someone who fills his own gaps. Soon the mood turns. As Geon Tae’s attitude changes, Hee Dong looks anxious and confused. In one still he stares sternly, and in another he keeps a sharp gaze even while someone grabs his collar. Trust slowly turns into suspicion.
Why He Said Yes?
Park Yoon Ho says he finished the script in a single sitting, fully absorbed from start to finish. By the end, he knew he wanted to be part of the project. He also decided that Hee Dong’s inability to hide his feelings was part of his charm, so he focused on letting those emotions show honestly in his actions and expressions.
| Detail | Info |
|---|---|
| Drama | The Substitute |
| Genre | Crime thriller |
| Lead character | Joo Hee Dong (Park Yoon Ho) |
| Co-stars | Cha Kang Yoon, Bae Hyeon Seong |
| Key conflict | Friendship vs. a dangerous deal before the CSAT |
| Premiere | November 23 |
The Friendship at the Core
The bond between Geon Tae, Nam Jae Yeop (Bae Hyeon Seong) and Hee Dong is expected to drive the drama’s conflict. Each stands in a different position, and a dangerous deal ahead of the exam begins to crack their friendship. That slow break in trust could be what makes the thriller hit hardest.
When to Watch?
The Substitute premieres on November 23. While you wait, you can watch Park Yoon Ho in Study Group. For more release dates, previews and watch guides, visit Technosports and browse our K-drama updates.
FAQs
When does The Substitute premiere?
It premieres on November 23.
It is a crime thriller about three students.
Who does Park Yoon Ho play in The Substitute?
He plays Joo Hee Dong, an honest and ordinary high school student.
His trust in a close friend slowly turns into suspicion.





