In the drama, Kim Boong Do (played by Ji Hyun Woo) is a man originally from the Joseon dynasty who has been transported to the modern age.
He comes to meet actress Choi Hee Jin (played by Yoo In Na) who comes to try and help send him back to his age. In the episode, the two come to visit a library to take a look at the Annals of the Joseon Dynasty, in hopes to find a way back to the Joseon Dynasty. During this time the hidden interest and feelings for each other begins to seep through before Yoo In Na comes to kiss Ji Hyun Woo in the library’s elevator.
The scene was said to have its difficulty in shooting as the height difference between the two actors is 22 centimeters (over 8 inches). In addition, it was revealed the kiss scene took over 10 tries to shoot successfully - perhaps the actors messed up a few times on purpose? [i bet he is :p]
The scene was unfold during the fourth episode.