Actor Kwak Hee Sung showed up and made an appearance in the two episodes of the drama. He showed a side of a creepy killer, killing Kim Tae Hoon.
On the 8th episode of SBS drama "Secret Door" broadcast on October 14th, Kim Moo (played by Kwak Hee Sung) followed the orders of his father Kim Taek (played by Kim Chang Wan), who was the leader of the Noron faction. To find the secret document, he started to stop Kang Pil Jae (played by Kim Tae Hoon) and went into his quarters without notice.
In this process of following orders, Kim Moo ran into Na Chul Joo (played by Kim Min Jong) and ended up losing the secret document. Kim Moo put the knife into Kang Pil Jae's throat and ended up killing him. After following Na Chul Joo, he started a duel with him. Here, it was revealed that the two had known each other for a while.
Meanwhile, SBS Monday/Tuesday drama "Secret Door" is a period drama that follows the conflict between King Yeong jo (played by Han Suk Kyu) and Crown Prince Sado (played by Lee Je Hoon). Kim Yeong Jo has an authoritarian ruling style whereas Crown Prince Sado insists on equality for all.
