[2] It was ranked 3rd hottest drama for the first half of 2021 based on KT's online video service (OTT) Seezn,[3] and ranked 5th in tvN's all-time Wednesday and Thursday series (based on a paid platform integrated with cable, IPTV, and satellite/provided by Nielsen Korea).

[4] Screenwriter Choi Ran was inspired by an elementary school murder case that occurred in Incheon, South Korea, in 2017.

'[7] The story follows detective Ko Moo-chi (Lee Hee-joon)'s attempt to catch a psychopathic serial killer, after witnessing a horrific incident as a child and dealing with his demons from the trauma.

The line-up included Mouse, where it will have its first French premiere in the international panorama category to be chaired by Florence Aubenas.

[35] The finale's real-time online viewership rate of TVING on the Korean network platform hit a record high of 90.6%.