"Signal" is an extremely ambitious drama. I watched without knowing anything at all about it (other than it involved cops), but it's hard to review it without giving parts of the story away. I'll spoil this review and say I am going to recommend you watch it, so you can stop reading now, and immediately start watching episode one the same way I did. If you want to know more about what you're possibly getting yourself into, keep reading. This drama is primarily a crime thriller. It claims to be adapted from "Memories of Murder", but I saw that movie, and the two only seem to relate on a surface level. What this show really focuses on are unsolved cold cases, and it uses a mysterious partnership between an ambitious cop from the past and a cynical cop from the present to attempt to solve them. The idea of manipulating the past to change the future is not new in KDramaland, but it is hard to do well, and this show manages to do it very well. Much of the show's appeal comes from the 3 main characters, and the actors who play them. Jo Jin Woong as Lee Jae Han is the ultimate everyman hero. His determination is inspiring, and frustrating to watch. He brought a humanity to the idea of what it takes to be an effective cop. Then there is Lee Je Hoon as Park Hae Yeong, another character with a lot of depth. I loved watching him go from being a cynical know-it-all to going above and beyond. I think his character was so well written, and liked that the more I learned about his backstory, the more I connected to his choices and actions. Then lastly there's Kim Hye Soo as Cha Soo Hyun. I love that she is a total bad@ss. I will admit that I was definitely more of a fan of her in present day, although I understand showing her transformation from how she started out. Watching their frustration, eagerness, regret, stubbornness, impetuousness, tears... made me have so much empathy for their characters, even though I didn't cry even once (and I am a cry baby). The supporting cast is good, really good, even when their characters aren't the most likable. The cases themselves were also all interesting, which means I was never bored. Although there are romantic aspects to the plot, it's the partnership chemistry that drives the show, so reviews that call this a "romance" aren't really accurate. I will admit that I was more into the chemistry between Cha Soo Hyun and Park Hae Yeong, than her chemistry with Lee Jae Han. Some of the scenes when she was a rookie made her seem a little like an emo-stalker, which didn't seem as cute to me as it was meant to seem. I think their past was the only weak part in the plot for me, and although I understand why it was written that way, it made it seem like she was always overreacting when it came to her senior. Meanwhile, I wonder if I was the only one who sensed some kind of unspoken attraction between her and Hae Yeong. Fine, Was it just me? Wishful thinking? lol. Either way, I thought they worked really well together. I saw that some people complained about plot holes, which you will always find if you look hard enough. I thought this show did an excellent job of tying up loose ends, avoiding useless scenes, and answering questions. It may be confusing in the beginning, but it soon starts to make perfect sense. There are a few things that are left open ended, or without explanation, but I think keeping a little bit of mystery added to the story. The fact that the story is so cohesive is why I gave it such a high rewatch rating. I think it would be cool to see the whole thing again, now that I know whats's going on, and my guess is that I will see things differently than I did the first time, which is my favorite reason to rewatch anything. It's also not all depressing, or gruesome. They actually manage to find places to add some comedy, without it being glaringly inappropriate (well, there are the obligatory fart jokes... ) I should mention too that the OST fit the show very well, complimenting the atmosphere, but it's not something I feel compelled to listen to on it's own. Overall, this is a must see for any thriller fan, but still has enough appeal to convert fans of other genres. I don't agree that it's the greatest drama ever, or the most original ( I saw "Frequency"), but the fact that it has so many fans makes complete sense. This is one of those shows that it's really difficult to find fault with. From the very first episode I was sucked in, and I had to keep watching 3 more episodes just to see what happened next. This is the kind of drama that can make you lose sleep, because once one thing is resolved, a new equally/more interesting scenario begins. It's that way up to the very last episode, so I understand people being excited about a possible season 2. I know I would watch!