In "Hidden Identity" Lee Won Jong and Kim Beom found a piece of very definitive evidence that would uncover who the ghost was. The ghost had been a legendary hacker that they had tried to gather evidence on this hacker who had gotten into the National Intelligence Agency.
On the 4th episode of tvN Monday/Tuesday drama "Hidden Identity" broadcast on June 23rd, Teacher Jung (played by Kim Min Joon) had been murdered.
On this day, the members of the National Intelligence Agency sent Teacher Jung to the meeting point in order to capture and arrest the ghost. The ghost called the Teacher and said, "Have you met the mermaid? I'm looking forward to the ending. It's unfortunate that we can't watch it together."
This brought a change in the plot of drama. As soon as Teacher Jung said, "Thank you for everything until now." This was his last thank you as he was hit by a bullet that came out of nowhere. Afterwards, Jang Moo Won (played by Park Sung Woong) chased after the mermaid he mentioned in order to get to the bottom of the identity of the ghost.
Meanwhile, the new tvN drama "Hidden Identity" features Kim Beom, Lee Won Jong, and Yoon So Yi.
