What if my unborn child is a psycho?

What if you could identify psychopaths through a genetic test before they were born?

In South Korean drama Mouse, a face-to-face encounter with a psychopathic serial killer drives rookie detective Jeong Ba-reum (Lee Seung-gi) to unearth the truth behind the killer's behaviour with his partner Go Moo-chi (Lee Hee-jun).

The thriller drama explores the idea that psychopaths are naturally born rather than raised and challenges the ethics of identifying them before birth.

Here are four things to know about the drama and the cast.

The riveting plot was what attracted the main cast of the series.

Lee Hee-jun (The Legend Of The Blue Sea, 2016), 41, who plays a vengeful detective, was impressed by how meticulously plotted the script was.

He reveals that clues to solve the mystery in the ninth episode were planted as early as the first.

Actress Park Joo-hyun (Extracurricular, 2020), who plays a troubled high-school student with expertise in martial arts, was hooked by the plot as it was "filled with tension and did not have any dull moments".

"I read the entire script in one sitting without realising it," says the 26-year-old in an e-mail interview with The Straits Times.

"Unlike other thriller productions, the story did not feel cold."

The series poses the dilemma of whether parents should keep their unborn child if they find out their offspring is a psychopath.

If there were a genetic test similar to the one in the drama to find out if your unborn child could become a psychopath, would you try it?

Park initially said no. "No matter what others might say, my child is still my child," she says.

But she changed her mind after the filming of the series began.

"The dangers and the lack of mercy a psychopath can present hit me," she adds. "I would send my child for the test... for the greater good."

To play the award-winning producer of an investigative programme, actress Kyung Soo-jin (Eunhui, 2013) prepared for it by watching current affairs and cultural programmes and observing the producers. This was particularly crucial for her scene in the fifth episode, in which she hosts her programme Sherlock Hong-joo.

The 33-year-old says it was the most challenging part of the filming for her. She rehearsed the scene twice daily in the days leading up to the filming and the entire day right before it was filmed.

Likewise, Park did her homework by doing research on other characters similar to hers. "The extent of pain my character had to go through was so immense that I would not be able to relate to it. I had many concerns over how I should act how hurt and self-defensive she was."

To prepare for her role as a martial arts expert, Park not only attended training in an action school, but also picked up kickboxing.

"I managed to pick things up quickly since I have always liked working out," she says.

Her most memorable fight scene was the showdown with the killer in a cathedral, which was not just action-packed, but also emotionally draining as her character was avenging her grandmother.

Park hopes to keep playing strong female roles or characters who keep others safe - even if that may mean taking on more action scenes.