A contemporary medical thriller with a syringe full of twists, Hyper Knife follows Seok, a visionary neurosurgeon who demonstrates unparalleled skill with a scalpel. Addicted to the operating room and obsessed with honing her abilities, Seok suddenly finds herself shunned by her mentor and stripped of her medical license after uncovering a shocking truth. Refusing to let go of her life’s work, Seok continues to carry out back-alley operations for some of society’s least desirable individuals, until her former mentor comes asking for her help. Torn between the chance to successfully carry out an impossible operation or exact her revenge on the man who stripped her of her future, find out what Seok decides to do on Hyper Knife, exclusively on Disney+.
Learn more in this exclusive Q&A with Hyper Knife Director Kim Junghyun!
| Q. Can you tell us what made you decide to direct Hyper Knife? |
| It’s been a long time since a script made my heart race but Hyper Knife did just that. The characters, Seok and Deokhee, were incredibly intense and compelling. Normally, I read a script several times before deciding whether to take on a project, often questioning myself: “Can I really pull this off?” But with Hyper Knife, the decision was immediate. I was captivated by the characters, who were so unconventional for a Korean series, and by the narrative structure of the story, which was also very different from what we’re used to seeing on tv. I just knew I had to direct this series. |
| Q. One of the main highlights of the series is the relationship between Seok and Deokhee. What was your main focus when highlighting the dynamics between these two characters? |
| Tension and conflict are the two keywords that best represent the themes of Hyper Knife. The story revolves around a kind of battle between Seok and Deokhee, who, because of their deep, irreconcilable rift, spend years apart until they are pulled back into each other’s lives. To visually capture their battle, I aimed to create a stark contrast between the two characters. For the title footage, I used red shades for Seok and blue for Deokhee. Seok embodies explosive energy and expresses her emotions unapologetically, while Deokhee hides everything—he is incredibly cold, composed, and analytical, hence the use of blue to contrast with Seok’s red. The color contrast extended beyond the title sequence to costumes, lighting, and the overall visual tones for the characters: red hues were used to define Seok, while bluish tones were applied to Deokhee. The contrast was also captured in music. Given the nature of the character, heavy and dark sounds like the cello were used for Deokhee, while the music for Seok was designed to be lighter and breezy, as encapsulated by the oboe. Ultimately, however, Seok and Deokhee are two sides of the same coin. Towards the latter part of the story, I made an effort to highlight their shared traits through various techniques, such as using similar camera angles for the two characters. |
| Q. Eunbin’s character is very different from anything she’s portrayed in the past. How did you go about bringing out the intensity of her character? |
| She was already well-prepared to begin with. For this project, I think I relied on Eunbin and Kyunggu to take the lead as we filmed. We were all aligned on the direction of the series, so I was mostly observing the way they performed. When it comes to Eunbin, more specifically, I told her from the beginning of the project that I would transform how she looks—that I would completely break away from the goodness and innocence that often defined her previous roles. At times during filming, however, I wondered if I had pushed her too far in the opposite direction. I even asked her, “Are you sure you’re okay with this?” But she would respond, “You told me you would transform how I look.” She was fearless in that regard. |
| Q. Deokhee is able to hold his ground against Seok’s intense personality while also being able to provoke her. Was there any particular reason why you decided to cast Sul Kyunggu for the role of Deokhee? |
| Kyunggu is literally a living legend in Korean cinema. There was no doubt about giving him this role. However, as I mentioned earlier, while Seok gives off this explosive energy, Deokhee simply absorbs it all without ever revealing his true emotions—which I think could have easily made him an incredibly flat and boring character. But as the story progressed, Kyunggu infused his own thoughts and perspectives into Deokhee, giving the character a fascinating depth. The true genius of his performance lies in how effortless it feels. When we were editing the series in post-production, I could see why he made the choices he made for his performance. I loved it. |
| Q. I am sure that Eunbin and Kyunggu both have their respective charm, but as a director, it must have been an entirely different experience to see their synergy when they performed together. How did you find their chemistry? |
| I absolutely loved it. Their differences excited me—I was looking forward to the synergy they could create, given their contrasting backgrounds and roles they’d played in the past. On the surface, they might not seem like actors who would blend together, but I think their distinctive traits made their on-screen chemistry much more compelling. Off-camera, of course, they got along incredibly well, and I loved seeing them having a lot of conversations about the series. |
| Q. I heard that you used expensive surgical equipment and consulted a medical professor to ensure the accuracy of the medical aspects of the series. Can you share more details about this process? |
| While we could draw from our imagination for the genre elements, we had to ensure that the medical details were grounded in reality, which is why we paid close attention to accurately capturing those details. Before filming began, both the cast and production crew were given extensive training and guidance from the consulting doctor, who was always present on set during all surgical scenes. The doctor would even go so far as to take personal leave to be on set from early morning to late at night for certain scenes. He meticulously reviewed even the tiniest detail, including the hand gestures that doctors use during surgery. I think this effort added a strong sense of realism to the medical aspects of the series. For the brain surgery scenes, since we could not use real brain samples to film, we relied on incredibly lifelike models of the human brain, face, and other body parts. As far as I know, no other Korean series has portrayed brain operations in such extensive detail, and with the added support of CG, we were able to capture the details of the medical procedures effectively. |
| Q. I loved the music that heightened the sense of tension in the series. What kind of conversations did you have with the composer? |
| I had extensive discussions with the composer even before production began. What we eventually agreed on was music that, while somewhat familiar, would also feel fresh and unexpected. Beyond the genre elements, Hyper Knife is essentially about the emotional and psychological dynamics of two highly unrealistic characters. Given this aspect of the series, we wanted to maintain the tension typical of the genre but also introduce music that could catch viewers off guard, especially in scenes where the two characters interact. The composer took that vision and created a wonderful soundtrack based on classical music. |
