This sounds good reading the reviews but I found most of episode 1 boring, just the usual police thriller with nasty murders and I can not see much sci-fi. Then it gets interesting as he looks like catching the criminal and you are hooked into wanting to know what happens next. I find Choi Jin Hyuk's acting "wooden", but I suppose there's meant to be a contrast between him as the rough cop and Sun Jae as the cool, arrogant graduate cop. Much better with episode 2. The "transition" to the future was well handled. Others comment it is not convincing but you have to have some "suspension of disbelief", not work out every detail of how someone would adjust in that situation. Some of the violent scenes are too gory for me, I must say. But glad I stuck with it as it gets better with every episode. Sci-fi element at first seemed to be just a way of giving a twist to the story, then about half way it takes a central role again, as the way the characters' lives interact with each other in past and future becomes clearer. Very cleverly done. The only thing that bothers me is I wish they could do these shows without zero-ing in on the ghastly murders "as they happen" or the grisly photos afterwards. They look all too real for my liking. How about just a foot with the detectives turning away and making a terrified face? Anyway, leaving aside my sensitivity, what started as apparently just another plodding police thriller turned into a clever and riveting drama. Very moving finale, I wasn't quite sure what would happen until it did..Once again teaches me not to ditch shows based on impulsive reaction to first episode or two. Finally rates a 10/10*.