wow! this movie is something to watch! different side of won bin, ive never seen. that ahjussi really was mysterious, i was eager to know more and more about him. there are many flashbacks but it helped the suspense thrill and story line. if there's no flashbacks, it would be dreadful boring. I did not expect this movie to be action-packed! and i knew wonbin is someone who's good at taekwondo but never actually seen him use at least some of the skill in drama or tv or movie. this is a SHOULD WATCH movie!