"Yong Pal Yi," started off strong with dramatic opening scenes and impressive ratings.

The first episode reached the double digits in viewer ratings with 11.6 percent. While that is 2 percent less than the final episode of the previous drama "Mask," it's still impressive and landed the drama in first place.

Meanwhile, "Scholar Who Walks The Night," starring Lee Soo Hyuk, Lee Jun Ki, Kim So Eun and Lee Yu Bi, earned 8.5 percent of the ratings. "The Assembly" earned 5.3 percent, landing in third place.

Kim Tae Hee plays the heiress Han Heo Jin in "Yong Pal Yi." When the first episode opens, her character is in a coma, playing out the endless nightmare of being a passenger in a dangerous car chase that killed the car's driver. Surviving the crash that ensues is not enough. Distraught over the loss of her lover, she tries to kill herself by jumping through a plate glass window, ending up in a coma.

In an unrelated incident, the police visit the scene of a brutal attack against a gambling den. They figure there must have been plenty of injuries when the attackers burst through the windows of the illegal gambling den but where have all the injured victims gone? Ah, Yong Pal Yi, one of officers says. They know that a shady doctor known as Yong Pal Yi will treat anyone for money. What they don't know is that Yong Pal Ie Yi also Kim Tae Hyun, a gifted surgeon who works at a top hospital. Kim Tae Hyun, played by Joo Won, lives two lives. During the day, his hospital colleagues look up to him, even if they don't all believe he is ethical. At night, when he is Yong Pal Ie, he treats criminals in circumstances that really should be reported to the police.

According to the police he is a "quack who treats criminals in secret"

But from both the opening criminal and hospital scenes, you can tell that Yong Pal Yi is one capable doctor. He can pick up on the subtlest signs.

So, why is he treating people in secret at night?

That's the story behind 'Yong Pal Yi."

The opening minutes of 'Yong Pal Yi' show that the production company not only invested in top stars for its cast but the technology and set design needed to make them compelling.

It's not Joo Won's first time playing a doctor. He also played a doctor with Asperger's Syndrome in "Good Doctor." Kim Tae Hee's last drama appearance was in "Jang Ok Jung: Living For Love."