''Circle'' () is a 2017 South Korean

science fiction Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel unive ...

television series A television show – or simply TV show – is any content produced for viewing on a television set which can be broadcast via over-the-air, satellite television, satellite, or cable television, cable, excluding breaking news, television adverti ...

starring

Yeo Jin-goo Yeo Jin-goo (, born August 13, 1997) is a South Korean actor. Yeo began his career as a child actor, debuting in the film ''Sad Movie'' (2005). Nicknamed " Nation's Little Brother", he went on to play the younger characters of the lead roles in ...

Kim Kang-woo Kim Kang-woo (born July 11, 1978) is a South Korean actor. He is best known from his roles in '' The Taste of Money'' and '' The Missing''. Career Kim Kang-woo majored in Theater and Film at Chung-Ang University. In early, Kim work as singer in ...

Gong Seung-yeon Gong Seung-yeon (, born Yoo Seung-yeon on February 27, 1993), is a South Korean actress. She is best known for her roles in the film '' Aloners'' (2021) and television series such as ''Six Flying Dragons'' (2015–2016), ''The Master of Revenge ...

, and

Lee Gi-kwang Lee Gi-kwang ( ko, 이기광; born March 30, 1990), known professionally as Gikwang or Kikwang, is a South Korean singer, songwriter and actor. He originally debuted as solo singer with ...

. The series features two parallel plots set in the years 2017 and 2037, both centered on twin brothers' struggle with the discovery and development of an advanced

alien Alien primarily refers to: * Alien (law), a person in a country who is not a national of that country ** Enemy alien, the above in times of war * Extraterrestrial life, life which does not originate from Earth ** Specifically, intelligent extrater ...

technology that could either be a boon or bane for the entire human race. It aired on

tvN TVN may refer to: * TVN (Australian TV channel), a former horse racing channel * Televisión Nacional de Chile, a public broadcaster * TVN (Indonesia), a former television station; predecessor of Rajawali Televisi * TVN (Norway), or TVNorge, a comm ...

for 12 episodes at 23:00 KST on Mondays and Tuesdays from May 22 to June 27, 2017.

Synopsis

In the year 2007, before the main events of the drama, 11-year-old fraternal twin brothers Kim Woo-jin ( Jung Ji-hoon) and Kim Bum-gyun (

Kim Ye-joon Kim or KIM may refer to: Names * Kim (given name) * Kim (surname) ** Kim (Korean surname) *** Kim family (disambiguation), several dynasties **** Kim family (North Korea), the rulers of North Korea since Kim Il-sung in 1948 ** Kim, Vietnamese f ...

), along with their

neuroscientist A neuroscientist (or neurobiologist) is a scientist who has specialised knowledge in neuroscience, a branch of biology that deals with the physiology, biochemistry, psychology, anatomy and molecular biology of neurons, Biological neural network, n ...

father Dr. Kim Kyu-chul ( Kim Joong-ki), witness the arrival of a female

humanoid alien This list of humanoid aliens is a collection of various notable Extraterrestrials in fiction, extraterrestrial humanoid characters that appear in various works of fiction. Humanoid aliens have traits similar to that of human beings including up ...

(

). Out of pity and curiosity, the family brings the alien with them and adopts her as a member of the family. The twins become fond of her, especially Woo-jin who names her ''Byul''. By chance, Dr. Kim discovers Byul's secret: she had brought with her an advanced form of technology that can record, and even lock,

memories Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...

and convert them into

video Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syste ...

. In order to closely study this alien technology, Dr. Kim isolates himself from his family to work secretly on Byul in what he calls the "Beta Project." Dr. Kim never goes back home, making the twin Bum-gyun think Byul has taken their father

captive Captive or Captives may refer to: Arts, entertainment, and media Films * ''Captive'' (1980 film), a sci-fi film, starring Cameron Mitchell and David Ladd * ''Captive'' (1986 film), a British-French film starring Oliver Reed * ''Captive'' (1991 ...

, though Woo-jin believes their father has abandoned them. In 2017, Woo-jin (

), now a 21-year-old college student in

neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, development ...

, feels that a series of suicides in his university is somehow linked to Bum-gyun (

An Woo-yeon Ahn Byeong-ho (born 7 January 1991), better known by his stage name Ahn Woo-yeon, is a South Korean actor. He starred in TV series such as ''Five Enough'' (2016), ''Don't Dare to Dream ''Don't Dare to Dream'', also known as ''Jealousy Incarnat ...

), who has been searching for aliens, particularly Byul. While in pursuit of the case, Woo-jin meets Han Jung-yeon (

), a

computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...

student who, to his great shock, looks very much like Byul. She is also investigating the multiple suicides, all of which she thinks are actually murder. In 2037, South Korea is now divided into Normal Earth, a heavily polluted place where crimes are rampant, and Smart Earth, a clean, peaceful, and crime-free city. Kim Joon-hyuk (

) is a Normal Earth crimes detective who tries to get into Smart Earth to investigate a case of twin brothers who went missing in 2017. In doing so, he starts to uncover the dark truth lurking behind Smart Earth being “crime-free.” Each episode of the drama, except the last, contains two parts: ''Part 1: Beta Project'', which contains a plot set in 2017, and ''Part 2: A Great New World'', which contains a plot set in 2037. The two plots merge in the twelfth and final episode of the series, titled ''Circle: One World''.

Cast

Main

as Kim Woo-jin (''Beta Project'') / Circulate 3 (''A Great New World'') ** Jung Ji-hoon as young Woo-jin :a 21-year-old second-year university student in the Department of

Neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, development ...

in Handam University of Science and Technology in the year 2017; Bum-gyun/Joon-hyuk's "younger" twin brother and son of Dr. Kim Kyu-chul :In his younger years, Woo-jin was an enthusiast about

UFO An unidentified flying object (UFO), more recently renamed by US officials as a UAP (unidentified aerial phenomenon), is any perceived aerial phenomenon that cannot be immediately identified or explained. On investigation, most UFOs are id ...

s and

extraterrestrial life Extraterrestrial life, colloquially referred to as alien life, is life that may occur outside Earth and which did not originate on Earth. No extraterrestrial life has yet been conclusively detected, although efforts are underway. Such life might ...

. He witnessed (with Bum-gyun and Dr. Kim) the arrival on Earth of a female humanoid alien, which he names "Byul." His passion faded when his father disappeared with Byul. In 2017, he meets Byul (now Han Jung-yeon) once again and together they investigate the serial suicides in the university, with the help of Detective Hong Jin-hong. *

as Kim Joon-hyuk (born Kim Bum-gyun) ** Ahn Woo-yeon as 21-year-old Kim Bum-gyun **

Kim Ye-jun Kim Ye-jun ( ko, 김예준; born April 28, 2007), is a South Korean child actor. He is known for his roles in '' Misaeng: Incomplete Life'', ''Weightlifting Fairy Kim Bok-joo'', '' Rebel: Thief Who Stole the People'', '' Secret Mother'' and ''Art ...

as young Bum-gyun : (''A Great New World'') a 41-year-old violent crimes detective from Normal Earth in the year 2037; Woo-jin's "elder" twin brother and son of Dr. Kim Kyu-chul :Joon-hyuk enters Smart Earth to investigate cases happening within the supposedly "crime-free" city, with the help of Detective Hong Jin-hong and the alien hacker Jung-yeon a.k.a. Bluebird. Twenty years before (as Kim Bum-gyun) he was consumed with aliens on earth and had in facat been in a psychiatric hospital and prison for his seemingly mad behaviours. By 2017, he is investigating the series of suicide in Handam University of Science and Technology that he believed were brought about by aliens. He loses his memories later on; Detective Hong gives him his new name "Joon-hyuk" and he enters the police force. *

as Han Jung-yeon (a.k.a. Byul, Bluebird) :a humanoid extraterrestrial being whose arrival on Earth was witnessed by the Kim twins and their father. :During her arrival in 2007, Byul appeared naked to the Kims and was also

mute Muteness is a speech disorder in which a person lacks the ability to speak. Mute or the Mute may also refer to: Arts and entertainment Film and television * ''Mute'' (2005 film), a short film by Melissa Joan Hart * ''Mute'' (2018 film), a scien ...

, having no knowledge of any human

language Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of met ...

. She becomes close to Woo-jin, who gave her the name "Byul," and she learns how to speak

Korean Korean may refer to: People and culture * Koreans, ethnic group originating in the Korean Peninsula * Korean cuisine * Korean culture * Korean language **Korean alphabet, known as Hangul or Chosŏn'gŭl **Korean dialects and the Jeju language ** ...

. She is a semi-immortal being, i.e. she never ages and will look the same as long as she lives. She had brought with her an advanced form of alien technology that can record, and even lock, memories and convert them into video. She was taken for scientific research by the twins' neuroscientist father and later loses her memories. She is adopted by Professor Han Yong-woo who named her Han Jung-yeon. :In 2037 (in ''A Great New World''), she becomes a

hacker A hacker is a person skilled in information technology who uses their technical knowledge to achieve a goal or overcome an obstacle, within a computerized system by non-standard means. Though the term ''hacker'' has become associated in popu ...

under the codename ''Bluebird'', based from

Maurice Maeterlinck Maurice Polydore Marie Bernard Maeterlinck (29 August 1862 – 6 May 1949), also known as Count (or Comte) Maeterlinck from 1932, was a Belgian playwright, poet, and essayist who was Flemish but wrote in French. He was awarded the Nobel Prize in ...

's '' L'oiseau bleu''. *

as Lee Ho-soo : (''A Great New World'') an intelligent 26-year-old government employee in Smart Earth in the year 2037 :Ho-soo is unbelieving at first on the possibility of criminality in Smart Earth and sides with the government. He is tasked to keep watch on Joon-hyuk who is investigating cases in the "crime-free" city. Upon learning the truth from Joon-hyuk, he becomes confused, but later sides with Joon-hyuk and Bluebird to take down the unjust powers controlling Smart Earth.

Supporting

Part 1: ''Beta Project''

= People around Woo-jin

= *

Jung In-sun Jung In-sun (born April 25, 1991) is a South Korean actress. Filmography Film Television series Web series Television show Music video appearance Ambassadorship * Public Relations Ambassador for the 41st International Contempo ...

as Park Min-young : a 21-year-old medical student who fell in love with Bum-gyun in 2017. She helped Bum-gyun, Woo-jin, Jung-yeon, and Detective Hong Jin-hong in investigating the serial suicides in the university. *

Seo Hyun-chul Seo Hyun-chul ( ko, 서현철, born 19 May 1965) is a South Korean theatre, film and television actor. He is known for his supporting roles in various TV series and films. His better known works are: 2013 medical drama series '' Good Doctor'', ...

as Detective Hong Jin-hong : He is a police

detective A detective is an investigator, usually a member of a law enforcement agency. They often collect information to solve crimes by talking to witnesses and informants, collecting physical evidence, or searching records in databases. This leads th ...

who began investigating the serial suicides in Handam University of Science and Technology, along with Woo-jin, Jung-yeon, and Min-young. He becomes suspended due to his involvement with the case. * Kim Joong-ki as Dr. Kim Kyu-chul : He is the father of the twins Kim Woo-jin and Kim Bum-gyun (Kim Joon-hyuk). He is a neuroscientist specializing in treating

trauma Trauma most often refers to: * Major trauma, in physical medicine, severe physical injury caused by an external source * Psychological trauma, a type of damage to the psyche that occurs as a result of a severely distressing event *Traumatic i ...

, working together with fellow neuroscientist Han Yong-woo, taking advantage of Byul's special memory-controlling technology. * Shin Dam-soo as Detective Choi : Detective Hong's junior who is working for another boss

= Handam University people

= * Song Young-gyu as Han Yong-woo : He is a professor and the dean of the Department of Neuroscience in Handam University of Science and Technology. He once worked together with Dr. Kim Kyu-chul in treating traumas using Byul's special technology. He became Byul's father a year after she came on Earth. *

Han Sang-jin Han Sang-jin (born January 17, 1978) is a South Korean actor. He is best known for starring in television dramas such as ''Behind the White Tower'' (2007), '' Yi San'' (2007), '' My Too Perfect Sons'' (2009), ''Marry Me, Please'' (2010), and ' ...

as Park Dong-gun : an associate professor of the Department of Neuroscience in Handam University of Science and Technology * Shin Joo-hwan as Lee Hyun-suk : a third-year student and research assistant in the Department of Neuroscience in Handam University of Science and Technology.

Part 2: ''A Great New World''

= Normal Earth people

= * Kim Min-kyung as Dr. Park Min-young : In 2037, she has become a skilled doctor and Joon-hyuk/Bum-gyun's girlfriend. She would always help him during investigations, especially in times when her expertise is needed. *

as Detective Hong Jin-hong : He is reinstated in the police force as a member of the cybercrimes unit. In 2037, he helps Joon-hyuk in his investigations in Smart City. *

Oh Eui-shik Oh Eui-shik (오의식, born November 1, 1983) is a South Korean actor. Oh made his musical debut in 2006 and has since built up his acting skills in a number of plays and television drama. He is known for roles in television dramas such as '' O ...

as Lee Dong-soo ** Jung Joon-won as young Dong-soo (in ''Beta Project'') : a skilled

whom Joon-hyuk usually enlists during investigations. He was Woo-jin's former tutee. * Kwon Hyuk-soo as Detective Oh

= Smart Earth people

= *

Min Sung-Wook Min or MIN may refer to: Places * Fujian, also called Mǐn, a province of China ** Min Kingdom (909–945), a state in Fujian * Min County, a county of Dingxi, Gansu province, China * Min River (Fujian) * Min River (Sichuan) * Mineola (Amtrak ...

as Lee Hyun-suk : In 2037, he is now an employee in Human B *

as Park Dong-gun : In 2037, he becomes the South Korea's Minister of Science and Economy *

Nam Myung-ryul Nam, Nam, or The Nam are shortened terms for: * Vietnam, which is also spelled ''Viet Nam'' * The Vietnam War Nam, The Nam or NAM may also refer to: Arts and media * Nam, a fictional character in anime series ''Dragon Ball'' * ''NAM'' (video ...

as Yoon Hak-joo : Mayor of Smart City *

Lee Hwa-kyum Lee Yoo-young (Korean: 이유영; born January 23, 1995), better known mononymously as Yooyoung, later, the stage name was changed to Lee Hwa-kyum (Korean:이화겸), is a South Korean singer and actress. She is best known as a former member o ...

as Secretary Shin * Choi Ji-hun as Kim Min-ji

Others

* Cha Myung-wook as Park Jin-gyu * Jeon Suk-kyung (Voice) * Kang Chung-hoon (Voice) * Ryu Eun-ji (Voice) * Park Young-jae (Voice) *

Park Ji-a Park Ji-Ah (; born February 25, 1972), is a South Korean actress. She is a recurring actress in Kim Ki-duk's films, having appeared in five of his works from 2002 to 2008. Her performance in ''Breath'' was described as "terrific" by ''Variety'' a ...

as Woman Waiting for Bus (Ep. 1, Part 2) * Park Eun-ji *

Johyun Shin Jee-won (Hangul: 신지원; born April 14, 1996), better known by her stage name Johyun (조현), is a South Korean singer, rapper, actress and television personality. She was a member of girl group Berry Good from 2016 to their disbandment ...

as Announcer in ''A Great New World'' (Ep. 1) * Jang Ji-woo as Smart City Security Agent (Ep. 1, Part 2) * Jang Joo-hee *

Kim Sa-hee Kim or KIM may refer to: Names * Kim (given name) * Kim (surname) ** Kim (Korean surname) *** Kim family (disambiguation), several dynasties **** Kim family (North Korea), the rulers of North Korea since Kim Il-sung in 1948 ** Kim, Vietnamese fo ...

as Doctor in Smart City *

Choi Sung-jae Choi Sung-jae (born 18 July 1984) is a South Korean actor. Filmography Television series Film Awards and nominations References External links

* * 1984 births Living people South Korean male television actors South ...

as Humans B Central Control Room Agent * Kim Ji-sung as Kim Nan-hee * Tae-ha as Choi Soo-bin (Ep. 3 and 7, Part 2) :Lee Ho-soo's deceased girlfriend. * Ha Yoon-seo as Kang So-yoon *

Noh Haeng-ha Noh Haeng-ha is a South Korean actress. She is known for her roles in dramas such as '' Forever Young'', ''Through the Waves'', ''Nokdu Flower'', ''Doctor Detective'' and ''Joseon Attorney ''Joseon Attorney'' () is a 2023 South Korean telev ...

Lee Tae-kyung Lee Myung-hoon (born February 2, 1989) is a South Korean actor and comedian A comedian or comic is a person who seeks to entertain an audience by making them laugh. This might be through jokes or amusing situations, or acting foolish (a ...

as Section Chief Go

Original soundtrack

Part 1

Part 2

Ratings

In this table, the represent the lowest ratings and the represent the highest ratings. *

Notes

References

External links

* * * {{Kim Young-hyun TVN (South Korean TV channel) television dramas South Korean science fiction television series South Korean mystery television series 2017 South Korean television series debuts Television series by Studio Dragon Dystopian television series Fiction set in 2017 Fiction set in 2037 Television series about extraterrestrial life Television series about brothers Fiction about memory erasure and alteration Works about twin brothers 2017 South Korean television series endings Television series set in the 2030s Television series set in the 2010s