I think "Circle: Two Connected Worlds" is the perfect sci-fi binge drama I was hoping it would be. With only 12 episodes, and such a compelling story, I easily finished this in two days. The most interesting thing about this drama is how it's literally split into two different stories, so it almost feel like you are watching the original and the sequel at the same time, and you're basically waiting for the stories to eventually connect. The first part is set in 2017 (which is actually the past and called “Beta Project"), and it has more of a sci-fi thriller feel. This story centers around a disturbing trend of suicides at a school that are more than they seem to be. The second half is set in 2037 and has more of a sci-fi fantasy feel with a detective edge (called "Brave New World") which took a little more time to grow on me. I do think the fantasy world was imaginative, yet realistic, for just 20 years into the future (I want those phones), but I still was more into the the story set in 2017 involving the 2 brothers, the suicides, and this mysterious "being". The Brave New World part of the story has more of a dystopian society feel, that is equal parts "ideal" and creepy. I guess which you prefer may depend on what genre you prefer. Those looking for a romantic drama should know that this falls more in the category of bromance. The story centers around the relationship between twin brothers played by Yeo Jin Goo and Ahn Woo Yeon in the Beta Project episodes, and Gong Seung Yeon rounds out the trio as the mysterious Han Jung Yeon. There are so many twists in the story that I am hesitant to talk about any of the characters too much, but it's fun to figure out who's crazy, who can be trusted, and who the heroes will be. Yeo Jin Goo as Kim Woo Jin definitely has star quality that I remember from "The Moon that Embraces the Sun", and "Missing You", where I think he was better than his "older" counterparts. He is the deserving star of this drama and I think he did a great job. I was initially less impressed by Gong Seung Yeon and her blank face stare, but I really started to like her as well, and I'm impressed by how beautifully she cries. In the 2037 cast the stand out is Kim Kang Woo as Kim Joon Hyuk. It's initially very hard to figure him out which I think is a good thing for this kind of story. This is the first drama I have seen him in, so I had no expectations for him, and by the end he made me tear up. I also really loved Lee Ki Kwang as Lee Ho Soo, his reluctant side kick. This was another character that really grew on me as the show progressed. The rest of the cast, in both worlds, were really good, even when some were, almost comically, acting in an over the top manor. The villains in particular were definitely extra wide eyed crazy. But all the characters were played well, and those who had a matching future counterpart were matched pretty well. Even the kids were super cute, so I have no cast complaints. Now, the story is definitely full of complicated and confusing twists, and some of the logic may not work if you pay too much attention, but in general I thought they did a good job of keeping the story constantly interesting, especially when the two stories started to merge more. There may be some holes in the science that I'm sure you could find, but what I liked about the story was that it was more about the moral questions that the science brought up, than the scientific details. I think they hit on some really thought provoking questions like "What makes us who we are?", or "What creates inner peace?", or "Can science go to far?", or even "Should happiness trump all else?". Those are just a few of the things this drama touched on in this story that I thought were very interesting. There are some other thoughts and themes that would fall too close to the spoiler zone to mention here, so I will just sayI enjoyed the philosophical aspects of this drama as much as the story. I will say that I have mixed feelings about the end. I think the goal was to leave it open for possibilities of a sequel, or just to keep people thinking. Not every question is answered either, but I think everything that needed to be resolved was resolved, and the rest is just open for interpretation, or a season 2. I could see myself watching this again, because it's not drawn out, and it would be interesting to watch the story knowing how all the pieces fit. I admit that the fact that it's not very predictable is what kept me watching initially, but the story and characters are entertaining, and the surprise element isn't it's only appeal. Overall this is not the kind of KDrama I would usually watch, but I'm glad I expanded my horizons a bit. I do like sci-fi in general, and love Thrillers, and both of those elements were done well here. This may not be full of rom com antics, but it is not totally without some romantic elements. If you like endearing cops cracking the case, there's some of that too. It's also the perfect length, so there is absolutely no dragging storylines, or rushed endings. I know this personally opened me up to watching more dramas like this one. "Circle" didn't give me the obsessive feels that my favorite dramas give me, but sometimes a really good story told well is all you need!