Ji-woo then works for drug crime gang Dongcheon, led by Choi Mu-jin (Park Hee-soon).

With the help of Mu-jin and to uncover the reason for her father's death, Ji-woo joins the police force and becomes a mole for Dongcheon.

Ji-woo, using her fake name Oh Hye-jin, is assigned to work in the drug investigation unit in the Inchang Metropolitan Police Station.

On August 11, 2020 Netflix confirmed through a press release that it would distribute another Korean original series Undercover, to be produced by Studio Santa Claus Entertainment Co., Ltd. (named as Fleet Co., Ltd. at the time, and the same production house behind Lucky Romance, My Sassy Girl and Another Child), written by Life Risking Romance TV series writer Kim Ba-da and directed by Extracurricular TV series director Kim Jin-min.

[5] Actors Han So-hee and Lee Hak-joo previously worked together in the 2020 JTBC drama series The World of the Married.