K-Drama Review: ‘Circle Two Worlds Connected’ a Sci-fi and Thriller Story That You Will Love to Watch!


Circle (Two Worlds Connected)

Circle (Two Worlds Connected) is a sci-fi mystery drama which tells about two worlds from the past and future linked and affecting each other. The time plot takes place in 2017 and 20 years later in 2037. Each episode contains two parts, the first part is set in 2017 called “Beta Project” while the second part is set in 2037 called “Brave New World.” While this drama shows a lot of futuristic concepts, not many Korean dramas are brave enough to produce sci-fi based dramas. It seems that the most popular dramas come from romance, drama, and slice of life, but this drama brings a lot of attention and good reviews to all the concepts from the drama and even the soundtrack. So, are you curious to know more about sci-fi Korean drama Circle Two Worlds Connected? Check our review!

Drama Full of Plot Twists and Cliffhangers

As stated before, Circle is set up in two different periods of time, in 2017 and 2037. The story begins in 2017 where a college student (Yeo Jin Goo) tries to find the connection between an alien visitor and mysterious suicides on his campus.

In 2037, the world is divided in two with one that is disease and crime-ridden called Normal Earth and one that is a Utopian society called Smart Earth. Here, a violent crimes detective (Kim Kang Woo) also works to solve the same case from the past.


Woo Jin is the hero of our 2017 timeline, and he faces one difficulty after another on his quest for the truth. He’s always been skeptical of his twin brother, Kim Bum Gyu (Ahn Woo Yeon), who is obsessed with tracking down an alien. But when the mysterious suicides start happening, he finds himself right in the middle of some dangerous stuff.

Yeo Jin Goo was absolutely phenomenal as Kim Woo Jin. Fans are truly proud of how deep he played the Woo Jin character and really not disappointed. Circle was perfect at allowing him to showcase his intensity as Woo Jin goes through so many struggles and so much heartache. Then we have Han Jung Yeon (Gong Seung Yeon) as a mysterious girl in the 2017 timeline. While Bum Gyu is sure she is an alien, Woo Jin is left quite confused by her since she appears to be very human.


In the 2037 timeline, Kim Joon Hyuk is a detective on Normal Earth. When a rare crime happens on Smart Earth, he finds himself investigating a decades-old mystery and a conspiracy of huge proportions.

Kang Woo ends up having to work with Lee Ho Soo (Lee Gi Kwang) of Smart Earth. Everyone in Smart Earth is required to have a chip that keeps their emotions under control. And Ho Soo soon finds himself at odds with Kang Woo.


Lee Gi Kwang was a perfect fit for the character of Ho Soo with this sort of calm detachment. While he’s a sort of nemesis at the beginning, Ho Soo is in for a difficult ride as he learns that the Smart Earth he is completely invested in is not so perfect. He has his own journey to go on as he learns the truth.


So how did Circle do as a whole? Did it live up to my expectations? My answer is a resounding YES! First, it completely nails the science fiction genre. With a plot that focuses on aliens, futuristic technology with small chips that control your emotions, altering memories, and a dystopian future divided into a disease and crime-ridden Normal Earth and a Utopian Smart Earth, you really couldn’t get more into the genre. It’s like they threw as many sci-fi tropes as they could into the story, and it somehow worked beautifully.

The writing for this drama was brilliant with layered characters that are so well developed. There is such an intriguing mystery that is put in place right from the get-go, and it is perfectly woven between the two timelines. The pace is fast and full of suspense from start to finish as there is a constant sense of urgency.


And there are always new plot developments with plenty of twists to keep things interesting. It’s hard these days to deliver true plot twists that the audience doesn’t see coming, but Circle delivered them repeatedly, and I was always wondering what was going to happen. It was truly amazing.

Circle also used a unique format by dividing each episode in half with the first half focusing on the 2017 timeline (Beta Project) and the second half focusing on the 2037 one (Grand New World). I wondered how this would play out and if it could be executed well, and it definitely was.

Both timelines were equally important to the story. In 2017, the mystery is just starting with a lot of development happening. You’re then left wondering how things ended up the way they are in 2037, but at the same time, there are still plenty of mysteries that need to be solved in that timeline. The world building was really excellent. Plus, you get double the cliffhangers since each part ends like a traditional episode. And there are some amazingly good cliffhangers!


Due to the nature of the two-fold narrative, this drama remained thrilling and suspenseful from beginning to end. The pacing was perfect. Maybe too speedy for some, but it was just right for me. From the very first episode, we hit the ground running. There are several major happenings, discoveries, and questions that develop in each half of each episode. Finding a dull moment, or just a moment to relax would be like trying to find a needle in a haystack. It works because of the genre. A thriller should be thrilling, and this is thrill done right. The number of plot twists they were able to conjure up and insert into each episode floored me. I found myself dreading the point where they might run out of tricks or the time where this streak of great writing and progression would hit a speed bump—but much to my relief, neither ever came. One of my favorite plot twists came toward the end where Bum Gyun and Circulate 3 were able to use their childhood memories of communicating through Morse code to their advantage, as a way to outsmart Park Dong Geun, who they knew would play back Circulate 3’s memories; an absolutely electrifying moment.

Know More About the Circle Two Worlds Connected Cast

amino apps
amino apps

Yeo Jin-goo as Kim Woo-jin


He’s a genius science major who has a twin brother. He and his brother were the first to see Byul (Han Jung Yeon) when they were kids. As a young adult, he is very practical and serious. He used to believe in aliens but somehow he seemed to have lost that fun and child-like behavior and thinks more rationally and is more into the “seeing is believing” phase of life.

He is the younger of the twins but is the smarter one, he developed a bond with Byul as a child and was always more outspoken. He has been trying to stop his brother’s obsession with aliens and refused to think he was speaking the truth.

When his brother goes missing he has been trying his best to uncover all of the scientific experiments behind the suicides of female students at his school and finding the links between it and his past.

He meets Han Jung Yeon who looks exactly like Byul from when he was a boy, his brother kept labeling her as an alien and who was behind the suicides and he’s very skeptical of her since what his brother told him but couldn’t find any evidence to prove it was really her until a certain item made the connection real.

Gong Seung Yeon as Han Jung Yeon


She came to earth 20 years ago and has not aged since. She lost her memories by asking the boys’ father – a Neuroscientist to erase them to avoid other scientists trying to use her knowledge to control humanity and change the world.

She was emotionless and rarely spoke until after she lost her memories she became more human. Her father was partners with Woo-Jins dad who adopted her in order to use her once her memories returned.

She develops affection for Woo-Jin as a boy because he was kind to her, as a teenager she also felt affectionate to Woo-Jin and becomes a very genius hacker in 2037.

Kim Kang Woo as Kim Joon Hyuk

He is a police officer in the year 2037. He has no memories of his past and used the video footage of Woo-Jin to provide some insight into his past.

He is very righteous and doesn’t like the stable care system or smart earth at all. He doesn’t do well with people in authority and has been trying to find his brother.

It was uncertain which of the twins he was until midway through the series. This left a huge shocker on my mind.

He’s very agile and well trained. He always plays with his Rubix cube when he’s thinking (gave a hint to make you think which twin). He’s full of humor and loves to joke around with Ho Soo. I honestly fanned him on DramaFever after watching him act in this show.

Lee Ki Kwang as Ho Soo


He was an employee on Smart earth. He followed the rules and did not like disorder. When Joon Hyuk and he meet, they do not get along and he is seen to be very arrogant and a no-nonsensical person.

He starts to have flashes of his memory restored courtesy of Bluebird and does not like what he sees. He had a rebellious phase because he was scared and tried to stop Joon Hyuk from uncovering the truth.

In the end, he becomes his own self and helps Joon Hyuk and Bluebird uncover the truth.

OST from Circle Two Worlds Connected

OST Part 1: “Walk With Me” by Kwak Jin-eon

OST Part 2: “Alive by Uji (Bestie)” feat. Andup

Reasons Why You Should Watch Circle Two Worlds Connected

  1. Original plot/ storyline

I loved the innovative dual formatting of this show. Not only did it allow for an elaborate storyline and rich character development, but also enabled amazing plot twists with double the cliffhangers. It was like getting two sophisticated stories in one, and that is no easy feat. These days, some, if not most, K-drama writers can’t even keep one story straight let alone interesting. Circle managed to create two different plot lines that were each compelling in their own right, and then converge them for what I’d deem one of the most clever and well-executed climaxes in k-drama history. The sci-fi genre is not often covered in k-drama and if it is, it’s not usually done very well in my humble opinion. This drama not only revived the genre but tackled it in such a revolutionary way. So much can be unpacked from this show. It wasn’t just visually pleasing or fun to watch, it was contemplative and filled with profound commentary on relevant, controversial topics.

2. Significant and deep themes

I think the drama ultimately aims to deliver the message that our memories are a crucial part of what makes us human, but also a foundation for our identities. This is the message Woo Jin gives to the troubled Byul, who wants to live a human life as Han Jung Yeon. It makes us think about humanity.

Apart from being central to human identity, the drama touches on another important role that memories play. That is—they force us to take accountability for our actions, both good and bad, which is why the concept of a crime-free community was simply a myth; an illusion. It wasn’t that the community was crime free, it was that by erasing memory— past criminal acts, consequences, and accountability were all extinguished along with those memories. People who had hurt others were able to walk around without taking any responsibility for their past crimes, adding to the trauma of their victims.


3. Thoughtful Character Development

Most of the characters, if not all, were developed extremely well. There was significant character growth for many, but one of my favorites, in particular, was Lee Ho Soo. It was gratifying to witness his transition from one end of the spectrum to the other. It took a significant amount of time for Ho Soo to come to terms with what was going on, but ultimately, after realizing the importance of memory—especially when it came to accountability and identity—he decided to take Bum Gyun’s side. Ho Soo ended up becoming a key part of the team that took down Human B, and it was heartwarming to watch his connection and relationship with Bum Gyun grow stronger over time. By the end, you could tell the pair really cared for and appreciated each other despite their bumpy beginnings and all the chaos that happened in between.

So, what are your thoughts about this drama? For me, it’s worth the watch, even more so if you love sci-fi and mystery! I give it an 8.5/10 rating!