Usually, Korean Thriller movies lose the plot towards the end but this one doesn't.
Right from the bat, it's bang on.
A focused plot is like a clean slate.
Each and every minute is a hell lot interesting to watch.

The plot isn't baffling, it's based on surveillance but the execution and theme predominantly rise up the movie to another level.
And on top of that combine it with the acting of Jung Woo Sung and Han Hye Joo.
Voila Perfection achieved.

The only reason I've given this a 9.5 is the ending.
And once you watch the movie you'll get the reason.
Don't miss it.
It's as real as it gets.
I enjoyed it a lot.