Hyper Knife ending explained and Season 2 renewal possibilities explored: What happened to Choi Deok-Hee?

Hyper Knife starring Sul Kyung-gu and Park Eun-bin aired the final episodes 7 and 8 on April 9, 2025, on Disney+. Hyper Knife is a story about Jung Se-ok (Park Eun-bin), a once-promising surgeon now living a disgraceful life by performing illegal operations.

Her life was ruined by her former mentor, Choi Deok-hee (Sul Kyung-gu). Jung Se-ok's life takes a new turn when Choi Deok-hee returns and requests her to perform a surgery on him. In the finale episode of Hyper Knife, Choi Deok-hee goes into hiding, away from Jung Se-ok, as he does not want her to perform a surgery before the time he had planned.

Choi Deok-hee becomes a criminal suspect in the eyes of the public, as he takes the blame for Jung Se-ok's crimes as well. Despite Jung Se-ok begging him to have the surgery done as soon as possible, Choi Deok-hee delays it.

The drama ends on a cliffhanger, as it does not clearly show whether Jung Se-ok will be successful in her operation on Choi Deok-hee. This hints at a potential second season renewal; however, Disney+ and the production team of the drama at Disney+ have yet to confirm the same.

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Hyper Knife ending explained: What lesson did Choi Deok-hee want to teach Jung Se-ok?

In episode 7 of Hyper Knife, Jung Se-ok reviewed the real CT scan of Choi Deok-hee's brain and learned that his condition was extremely critical. This may even lead him to his death. She decided that she would perform the surgery as soon as possible and started preparing for it. She met gangster Kim Doo-bong, who assured her that he would help her whenever she needed.

Detective Yang Dong-yeong saw the blurry CCTV footage of Min Hyeon-ju's murder, realizing it was Choi Deok-hee. He met Choi Deok-hee personally and asked him why he killed Min Hyeon-ju.

Choi Deok-hee came clean and threatened Yang Dong-yeong, warning him that both of them could be implicated. He advised Yang Dong-yeong to be more careful, considering he had a family.

Later, Choi Deok-hee and Jung Se-ok met at Kim Ki-young's funeral. He revealed that he killed Ki-young's father, Myeong-jin, as he wanted to take Jung Se-ok to LA under his guidance. However, Kim Myeong-jin overworked the surgeons under him and ruined many lives. Choi Deok-hee killed Kim Myeong-jin as he did not want the same to happen with Se-ok.

Jung Se-ok questioned him about why he kicked her out back in college. She expressed that he seemed embarrassed when she found out that he was a murderer. However, she was excited as Choi Deok-hee was just like him.

Choi Deok-hee stated that this was the reason why, as it was not normal to celebrate that one's professor is a murderer. She then stated that despite what he did to her, she did not want him to die and would perform the surgery.

The next day, Jung Se-ok was called by Yang Dong-yeong for interrogation regarding Min Hyeon-ju's murder. However, he could not get her to confess that Choi Deok-hee killed Min.

She called Choi Deok-hee and told him that she was prepared with the operating room for the surgery. At the same time, Choi Deok-hee, with Mrs. Ra's assistance, emptied his house and office at the hospital to go into hiding.

By the end of Hyper Knife episode 7, Jung Se-ok waited for Choi Deok-hee to come for the surgery. Instead, Alan Kim arrived and informed her that the professor would not be coming. Alan Kim informed her that Choi Deok-hee had been on self-medication for a long time and wanted her to do the surgery a month later, as per his original plan.

There was a scene where Choi Deok-hee tells Alan Kim that he wanted to die on the operation table, which will break down Jung Se-ok. However, this incident will ultimately help her improve in the future. Since she is now at her peak and has gained a lot of confidence, she needs to be grounded, and so he wanted to teach her a lesson.

At the same time, Choi Deok-hee called Yang Dong-yeong at his warehouse, where he showed him the body of Detective Wan-il stored in a fridge. Choi Deok-hee confessed to his crimes and then revealed a recording where Wan-il spoke about the detective's crimes. Choi Deok-hee said that he rechecked everything and that whatever Wan-il said was correct.

In the final episode of Hyper Knife, Choi Deok-hee told Yang Dong-yeong to catch him as he would not be alive by next month. On the other hand, Jung Se-ok tried her best to find him but failed to do so.

She met Alan Kim at Yeonshin Hospital; he showed her the operation room where the surgery on Choi Deok-hee would take place. Alan told her that he was on her side and that he bet on her skills that she would save Choi Deok-hee.

Mrs. Ra reached out to surgeon Han and asked him to look out for Choi Deok-hee. Han spent the next few days with the professor but didn't inform Jung Se-ok about it. Meanwhile, Jung Se-ok used her connection with Kim Doo-bong and asked him to find out the location of Choi Deok-hee. Kim Doo-bong met Choi Deok-hee, who convinced him to follow his plan by not helping Jung Se-ok.

Later, in Hyper Knife episode 8, Jung Se-ok met Yang Dong-yeong to tell him that she would save Choi Deok-hee no matter what. Yang Dong-yeong advised her not to do so because if the professor dies, he would be saved. Yang Dong-yeong tried hurting her hand so that she couldn't perform surgery, and in return, Jung Se-ok ended up killing him with her knife.

She called Kim Doo-bong and asked him to pass the phone to Choi Deok-hee. She informed him that she had killed Yang Dong-yeong asked him to come. Choi Deok-hee rushed to the scene, and the two had a huge argument.

She asked him why he was doing this to her, and he responded that this was his last lesson for her. Jung Se-ok said she didn't want to learn anything anymore but wanted him to stay alive.

Choi Deok-hee was stubborn and did not listen to her. He then took away the car, which had Yang Dong-yeong’s body.

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Hyper Knife season 2 renewal possibilities explored

By the end of the final episode of Hyper Knife, Jung Se-ok, her team, and Alan Kim are seen preparing for Choi's surgery. She met Choi Deok-hee before the operation, and he tried to thank her, but she stopped him. She told him that he should wait until after the surgery, as she would save him. The drama marks the end of Hyper Knife’s first season with Jung Se-ok performing the surgery.

It is unclear whether Choi Deok-hee is alive or not. The epilogue showcased that Mrs. Ra met Seo Yeong-ju and Jung Se-ok, making a deal about a seemingly illegal operation.

This operation involves the director of a neurology hospital who does not trust his own surgeons but wants Jung Se-ok to do so. The epilogue also reveals that Mrs. Ra saved Jung Se-ok's puppies before the arson.

The unsolved question regarding Choi Deok-hee increases the chances of a second season. However, Disney+ has not yet confirmed the renewal.

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All eight episodes of Hyper Knife are available on Disney+.