[3][4] Guardians tells the story of a group of four people who team up to serve justice after losing their loved ones to criminals.

They want to give these criminals the punishment that they deserve, and take matters into their own hands as the justice system in South Korea fails to capture the culprits.

The series is based on a script by rookie Kim Soo-eun which became the second placer in the 2016 MBC TV Drama Screenplay Competition in Miniseries category, behind Radiant Office which script was written by Jung Hoe-hyun.

[18] "The Guardians" marks Shin Dong-wook's return after being diagnosed with CRPS, a cripplingly painful illness in 2010.

[19] First script reading took place March 29 at MBC Broadcasting Station in Sangam, Seoul, South Korea.