My Secret Terrius

My Secret Terrius is a 2018 South Korean television series starring So Ji-sub, Jung In-sun, Son Ho-jun and Im Se-mi. It was aired on MBC from September 27 to November 15, 2018 on Wednesdays and Thursdays at 21:55 (KST).

Synopsis
A woman named Go Ae-rin (Jung In-sun) loses her husband. Along with her neighbour Kim Bon (So Ji-sub), who was an NIS agent, they discover the truth behind her husband's involvement in a huge conspiracy. And they succeeded in their plans

Main

 * So Ji-sub as Kim Bon (Terrius)
 * A legendary black ops agent at the National Intelligence Service (NIS).


 * Jung In-sun as Go Ae-rin (Alice)
 * A single mother who finds herself getting caught up in solving a conspiracy with Kim Bon.


 * Son Ho-jun as Jin Young-tae
 * A former con man who holds the key to a mysterious incident that Go Ae-rin and Kim Bon are involved in.


 * Im Se-mi as Yoo Ji-yeon
 * An NIS agent who is cold on the outside, but warm to Kim Bon, whom she has feelings for.

NIS agent

 * Um Hyo-sup as Shim Woo-cheol
 * Head of the NIS who values patriotism, loyalty and camaraderie.


 * Seo Yi-sook as Kwon Yeong-sil
 * Second-in-command and deputy director of the NIS. She is an ambitious, cold and calculating woman who hopes to take control of the agency, and who holds a secret about the conspiracy.


 * Kim Sung-joo as Ra Do-woo/
 * A genius hacker who is rebellious. He likes Yoo Ji-yeon.

KIS agent
Kingcastle is the housing complex where both Kim Bon and Go Ae-rin live. A closely bound community, it has a Kingcastle Information System (KIS).
 * Kim Yeo-jin as Shim Eun-ha
 * A woman with superb organizing and investigative skills, she is the chief of KIS.


 * Jung Si-ah as Bong Sun-mi
 * A KIS agent who has a crush on Kim Bon.


 * Kang Ki-young as Kim Sang-ryeol
 * A househusband, the only male KIS agent in the team.

Others

 * Yang Dong-geun as Cha Jung-il
 * Park Ji-hyun as Clara Choi
 * Kim Gun-woo as Cha Jun-soo
 * Ok Ye-rin as Cha Joon-hee
 * Hwang Ji-ah as Jo Seo-hyun
 * Lee Joo-won as Jo Seung-hyun
 * Kim Dan-woo as Han Yoo-ra
 * Oh Han-kyul as Kim Seung-gi
 * Jasper Cho as K
 * Lee Hyun-geol as Park Soo-il
 * Kim Byeong-ok as Yoon Choon-sang
 * Kim Ji-eun as Yong-tae's secretary
 * Park Soon-cheon as Lee Ji-sook
 * Mirosław Zbrojewicz as a following spy
 * Mateusz Bąkowski (Polish pianist, teacher music)

Special appearance

 * Kim Myung-soo as Moon Sung-soo
 * Head of the national security at the Blue House.


 * Nam Gyu-ri as Choi Eun-kyung
 * A nuclear physicist from North Korea, and Kim Bon's ex-girlfriend.


 * Yoon Sang-hyun as Yoo Ji-sub (ep 17, 19 & 20)
 * Obgyn surgeon, brother of Yoo Ji-yeon


 * Lee Jun-hyeok
 * a shaman (ep. 11)

Production

 * Lee Yoo-young and Yoo In-na were offered the female lead role but declined.
 * The first script reading took place in late June, 2018 at MBC Broadcasting Station in Sangam, South Korea.