Hyper Knife is a South Korean medical crime dark drama running eight 1-1/4 hour episodes on Disney+.

Jung Se-ok (Park Eun-bin - The King's Affection, Extraordinary Attorney Woo) is a brilliant brain surgeon but disgraced and I assume not licensed so she does black market brain surgery for criminals and such. Enter her former mentor Choi Deok-hee (Sui Kyung-gu) who needs her skill to perform brain surgery on him. But she hates him so much she's not willing to be rehabilitated in return for saving his life.

The series is Se-ok living her life while Deok-hee slowly turns the screws driving her into a corner where she will have to do the surgery. One of those screws is the police investigating a murdered nurse who was trying to blackmail Se-ok but turns out Se-ok is quite willing to murder people who get in her way as she does again later. But Deok-hee's secrets are slowly revealed and turns out he's as much a psychopath as she is.

It's a short series but quite tense with several plot twists. Park Eun-bin has a wonderful performance playing a psychopath with anger issues (she does a lot of yelling). The murders I found a bit disturbing as people die kind of slowly, for example the nurse is strangled by Se-ok with a medical tube from behind and that takes a minute of writhing (slower than real life but fairly long for a tv series). So it's good that this is only eight episodes as the tension would be maybe too much over 16 episodes (the story ramps up and never really lets you take a break).

Good intense series not really my type but I'm willing to watch Park Eun-bin tearing up the screen.