One thing about Korean thrillers is that they're disturbing & devastating as much as it is possible to make one feel so because I'm not going to exaggerate, this is one of those movies which will take your sleep away for a week. The movie's plot is heavy with mind staggering twists & the ending will definitely leave a heartsick & depressing impression on the viewers (no matter how 'sakt' you are, you will succumb to this movie).