# My Secret Terrius (내 뒤의 테리우스)
**My Secret Terrius** (내 뒤에 테리우스; also released as *Terius Behind Me*) is a 2018 South Korean television series broadcast by MBC that combines spy action, comedy, and romance. It stars [So Ji-sub](https://www.edgepedia.org/so-ji-sub) as Kim Bon, a legendary National Intelligence Service (NIS) black agent living under cover as a babysitter, and Jung In-sun as Go Ae-rin, the widowed mother of twins who lives next door. The series aired from September 27 to November 15, 2018, in 32 half-hour episodes.[1](https://www.hellokpop.com/review/k-drama-review-my-secret-terrius/) • [2](https://content.mbc.co.kr/program/drama/__icsFiles/afieldfile/2018/10/16/mysecretterrius.pdf)
| Key fact | Detail |
|---|---|
| Original title | 내 뒤에 테리우스; English titles *My Secret Terrius*, *My Secret, Terrius*, and *Terius Behind Me*[3](https://www.justwatch.com/in/tv-show/my-secret-terrius) |
| Broadcast | MBC, September 27 to November 15, 2018; 32 episodes[1](https://www.hellokpop.com/review/k-drama-review-my-secret-terrius/) |
| Director / writer | Park Sang-hoon (director); Oh Ji-young (writer)[2](https://content.mbc.co.kr/program/drama/__icsFiles/afieldfile/2018/10/16/mysecretterrius.pdf) |
| Main cast | So Ji-sub (Kim Bon), Jung In-sun (Go Ae-rin), Son Ho-jun (Jin Yong-tae), Im Se-mi (Yoo Ji-yeon)[1](https://www.hellokpop.com/review/k-drama-review-my-secret-terrius/) |
| Ratings | Episodes 11 and 12 recorded 8.2% and 9.9% (Nielsen Korea, Seoul capital area) with a peak of 10.7%, first in its time slot[4](https://enews.imbc.com/Tpl/View/244991) |
| Awards | 2018 MBC Drama Awards: viewer-voted Drama of the Year and the Daesang for So Ji-sub; 2019 31st Korean PD Awards TV drama work award[5](https://movienote.kr/my-secret-terrius-tv-81211/) |
| Filming locations | South Korea and Poland[6](https://k-popped.com/2018/10/exclusive-so-ji-subs-first-experience-acting-with-kids-in-my-secret-terrius/) |
## Premise and plot
Kim Bon was the NIS's top black agent. Three years before the story begins, he lost his fellow agent and girlfriend Choi Yeon-gyeong during a defection operation and was himself accused of being an internal spy. Believing a third party and a mole inside the NIS were responsible, he disappeared to investigate, living quietly in the apartment complex KingCastle.[2](https://content.mbc.co.kr/program/drama/__icsFiles/afieldfile/2018/10/16/mysecretterrius.pdf)
Go Ae-rin, a mother of boy-girl twins who had left her career to raise them, loses her husband to a sudden heart attack and must find work. At her new job she stumbles on a secret of the Korean office of [Cornerstone](https://www.edgepedia.org/cornerstone), an international military-industrial complex, and becomes entangled with Kim Bon, who realizes her husband's death is connected to the conspiracy he has been chasing.[2](https://content.mbc.co.kr/program/drama/__icsFiles/afieldfile/2018/10/16/mysecretterrius.pdf) • [3](https://www.justwatch.com/in/tv-show/my-secret-terrius) To protect Ae-rin's family and gather leads on a defense-industry lobbying case, Kim Bon volunteers as babysitter to her twins, Joon Soo and Joon Hee.[7](https://dryedmangoez.com/2021/01/21/good-ol-review-a-perfect-balance-makes-my-secret-terrius-a-bright-charming-and-exciting-series/)
The supporting cast includes con man [Jin Yong](https://www.edgepedia.org/jin-yong)-tae (Son Ho-jun), who becomes Ae-rin's boss at a front company; NIS agent Yoo Ji-yeon (Im Se-mi), an old friend of Kim Bon who joins the case; ambitious NIS chief Kwon Young-sil (Seo Yi-sook), who has been hunting Kim Bon since the failed mission; and NIS director Shim Woo-cheol (Uhm Hyo-seop).[7](https://dryedmangoez.com/2021/01/21/good-ol-review-a-perfect-balance-makes-my-secret-terrius-a-bright-charming-and-exciting-series/) • [3](https://www.justwatch.com/in/tv-show/my-secret-terrius)
## The KIS and the comedy of surveillance
A distinctive element of the series is the KingCastle Information System (KIS), a network of housewives (and one househusband) at the apartment complex, led by characters played by Kim Yeo-jin, Jung Si-ah, and Kang Ki-young. Their gossip-sharing and surveillance capabilities are played as rivaling a government spy agency, and the show's humor comes from the intersection of this domestic intelligence network with the NIS plotline.[7](https://dryedmangoez.com/2021/01/21/good-ol-review-a-perfect-balance-makes-my-secret-terrius-a-bright-charming-and-exciting-series/)
Reviewers highlighted the balance the series struck between espionage, domestic comedy, and romance. So Ji-sub described the show as a combination of spy/action, romance, and comedy, and noted that he trained at a martial arts school for the action scenes.[6](https://k-popped.com/2018/10/exclusive-so-ji-subs-first-experience-acting-with-kids-in-my-secret-terrius/)
## Production
The series was directed by Park Sang-hoon, whose earlier credit is *Radiant Office* (2017), and written by Oh Ji-young, who wrote *Shopaholic Louis* (2016).[2](https://content.mbc.co.kr/program/drama/__icsFiles/afieldfile/2018/10/16/mysecretterrius.pdf) It was So Ji-sub's return to television after a two-and-a-half-year hiatus, and his first time acting with children in a TV drama; he called the experience fun but said he struggled at times alongside the two child actors.[6](https://k-popped.com/2018/10/exclusive-so-ji-subs-first-experience-acting-with-kids-in-my-secret-terrius/)
**Poland shoot.** Part of the drama was filmed in Poland, which a Japanese program guide describes as the first Polish location shooting for a [Korean drama](https://www.edgepedia.org/korean-drama). So Ji-sub said the Polish scenes were shot during an autumn heatwave, with thick costumes, and that very few people recognized him there.[6](https://k-popped.com/2018/10/exclusive-so-ji-subs-first-experience-acting-with-kids-in-my-secret-terrius/) • [8](https://vod-sanpo.com/terrius/)
## Ratings and reception
The series held the top position in its Wednesday-Thursday mini-series slot. Episodes 11 and 12 recorded 8.2% and 9.9% in the Seoul capital area (Nielsen Korea), with a momentary peak of 10.7%, and posted 2049 demographic ratings of 3.8% and 5.2%, first among Thursday programs.[4](https://enews.imbc.com/Tpl/View/244991) A Japanese program guide lists an average rating of 8.5% and a peak of 10.5% for the run.[8](https://vod-sanpo.com/terrius/)
At the 2018 MBC Drama Awards, the series won the Drama of the Year award chosen by viewers, and So Ji-sub received the Daesang (grand prize). Jung In-sun won the female Excellence Award in the Wednesday-Thursday mini-series category, Kang Ki-young won a supporting-actor award, and Kim Gun-woo and Ok Ye-rin, who played the twins, received youth acting awards. The series also won the drama work award in the TV category at the 31st Korean PD Awards in 2019.[5](https://movienote.kr/my-secret-terrius-tv-81211/)
## The coronavirus storyline
In the second half of the series, episodes 10 and 11 center on a plot in which a powerful pharmaceutical company stages a fake terrorist attack to recreate the fear climate of the 2002-2003 SARS epidemic, by infecting the South Korean Health Minister who declined to outsource vaccine production to the company; the company has developed a mutated virus with a mortality rate of around 20%.[9](https://www.wired.it/play/televisione/2020/03/11/my-secret-terrius-serie-coreana-coronavirus/) The series also includes an explanation of coronavirus mortality, given as between 2% and 4%, compared with 10% for SARS, and of how the virus transmits.[9](https://www.wired.it/play/televisione/2020/03/11/my-secret-terrius-serie-coreana-coronavirus/)
When the COVID-19 pandemic began in early 2020, this 2018 storyline drew renewed international attention. Wired Italia profiled the series in March 2020 under a headline calling it the Korean series that spoke of the coronavirus in 2018, and viewers on social media noted the coincidence while watching the show during the pandemic.[9](https://www.wired.it/play/televisione/2020/03/11/my-secret-terrius-serie-coreana-coronavirus/)
## Distribution
The series has circulated internationally under several titles. It was added to Netflix UK on February 1, 2020, and later removed from that service.[10](https://uk.newonnetflix.info/info/81085163) It has been available on Kocowa in the United States[11](https://www.moviefone.com/tv-shows/my-secret-terrius/d9NNMWfGVPc9w3Sr8VzS24/where-to-watch/), and in India it has streamed on VI movies and tv and free with ads on Amazon MX Player.[3](https://www.justwatch.com/in/tv-show/my-secret-terrius) A Japanese guide notes that the 32 broadcast episodes are consolidated into 27 episodes for streaming.[8](https://vod-sanpo.com/terrius/)
## References
1. [K-Drama Review: "My Secret Terrius", Hellokpop, November 19, 2018](https://www.hellokpop.com/review/k-drama-review-my-secret-terrius/)
2. [MBC program sheet: My Secret Terrius (synopsis, director, writer, character profiles)](https://content.mbc.co.kr/program/drama/__icsFiles/afieldfile/2018/10/16/mysecretterrius.pdf)
3. [My Secret, Terrius, JustWatch](https://www.justwatch.com/in/tv-show/my-secret-terrius)
4. ['내 뒤에 테리우스' 소지섭-손호준, 정인선 두고 팽팽한 신경전, iMBC 뉴스](https://enews.imbc.com/Tpl/View/244991)
5. [내 뒤에 테리우스, 무비노트](https://movienote.kr/my-secret-terrius-tv-81211/)
6. [So Ji Sub's first experience acting with kids in My Secret, Terrius, K-POPPED!, October 25, 2018](https://k-popped.com/2018/10/exclusive-so-ji-subs-first-experience-acting-with-kids-in-my-secret-terrius/)
7. [Good Ol' Review: A Perfect Balance Makes "My Secret Terrius" a Bright, Charming and Exciting Series, DryedMangoez.com, January 21, 2021](https://dryedmangoez.com/2021/01/21/good-ol-review-a-perfect-balance-makes-my-secret-terrius-a-bright-charming-and-exciting-series/)
8. [私の恋したテリウス～A LOVE MISSION～, 韓ドラ散歩道](https://vod-sanpo.com/terrius/)
9. [My Secret Terrius, la serie (coreana) che nel 2018 parlò del coronavirus, Wired Italia, March 11, 2020](https://www.wired.it/play/televisione/2020/03/11/my-secret-terrius-serie-coreana-coronavirus/)
10. [My Secret, Terrius on Netflix UK, New On Netflix UK](https://uk.newonnetflix.info/info/81085163)
11. [Where to Watch My Secret, Terrius, Moviefone](https://www.moviefone.com/tv-shows/my-secret-terrius/d9NNMWfGVPc9w3Sr8VzS24/where-to-watch/)
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*Topic: Encyclopedia › Arts and culture › Screen and stage › Film and television › Series and fictional screen worlds › International serial drama and telenovelas › East Asian drama series › Korean contemporary drama › Thriller, crime, and mystery series › Spy and action thrillers*
*Initially written Sep 17, 2026 · Reviewed: Sep 18, 2026; Sep 30, 2026; Oct 25, 2026 · Edited: Sep 18, 2026; Sep 30, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license