As the detectives race to piece together clues, the killer taunts them by releasing a video online, revealing his next intended victim and plunging the country into further chaos.

Amidst the turmoil, the unit enlists the rookie detective, Park Sun-woo, whose strong sense of justice quickly catches Do-cheol's attention.

In September 2015, a month after the release of his film Veteran, Ryoo Seung-wan and production company Filmmaker R&K confirmed that they agreed to make a sequel, which they originally expected to be made within two to three years.

[8] In July 2022, FNC Entertainment announced that Jung Hae-in was offered a role in the film, succeeding Yoo Ah-in as the antagonist.

[9][10] In December 2022, Jung Hae-in was confirmed to have joined the cast, which would include Hwang Jung-min, Oh Dal-su, Jang Yoon-ju, Oh Dae-hwan and Kim Shi-hoo reprising their roles from the original film.