This is not a horror movie, it took me about half an hour to figure this out, but it's actually a drama using images of ghosts and nightmarish memories to tell the story of two different people, both dealing with personal demons, that happen to cross paths. Jeong-won falls asleep on the subway. He suddenly wakes up and just manages to jump out the door before it closes. As he looks back in the train he see two little girls sleeping, but they don't look right...the train drives off. The next day he here's on the radio that two little girls were found dead on the train that morning. Later at work he's hit on the head. When he get's home he starts seeing visions of the little girls in his apartment.
A year ago, Yeon, saw her baby murdered and ever since she's developed narcolepsy and passes out all the time.
A few days after his accident Jeong-won is doing some work at a psychiatrist office when he sees a Yeon and she captures his attention (it doesn't hurt that she probably the most beauitful woman in the world). As fate would have it she is a parishioner at his father's church and one evening, when he's visiting his father, Jeong-won is asked to give Yeon a ride home. They slowly strike up a strange relationship and from here on out things start to get kinda fuzzy for me.
I enjoyed the story, even if Ji-hyun Jun's role was too small, and I think maybe the moral of the story is if you allow tragedy to cut you too deeply you'll end up not living the rest of your life to it's full potential. I could be completely wrong, cause these two people went through some shit that was fucking rough and I really don't see how you could easily get over something like that. Personally I would just kill myself.
Maybe I'm completely wrong. If the story sounds interesting then you should check it out, but be warned it's slow and the ending is not a happy one.