One thing that K-Pop singers and groups like to do is to create a story video that accompanies their current single. While most music videos are confined to the song's start and end, Korean MVs are sometimes multi-part sagas that can last much longer than the typical four minutes. They can either feature the singers as characters in a story, or have other actors that play out the story.
A recent example of this that I have seen is 2PM's latest single, "Tik Tok." Unlike the Keisha song of the same name, this song has a more serious atmosphere. The members of 2PM portray the characters in this MV. Singer and actress Yoon Eun-Hye makes a special guest appearance on this song. The song is supposed to reflect the hidden love of 2PM. There's also a slightly creepy, stalkerish element to the song as well.
Without further ado, here is the music video, Part 1:
And Part 2:
The translated lyrics can be found here.