Ju Byeong-deok

An investigator who works alongside Gye Ji-ung.

Ko Won

A famous idol who has temporarily started working at the Seohan District Office.

Tak Cheon-hui

Gye Ji-ung's junior from the same department; she harbors a one-sided crush on him and attempts to solve cases independently.

Na Ok-hui

A serial killer who infiltrated the Seohan District Office under a false identity. She is responsible for the deaths of Gye Ji-ung's biological mother and your aunt, Lim Sun.

Cha Jae-seong

An official at the Seohan District Office who hires senior interns and assigns Lim Sun (you) to assist the prosecutors rather than performing standard intern duties.

Baek Cheol-gyu

A former hospital director searching for his wife's killer. He entrusted his bankbook to Lim Sun (you), asking to be notified if anyone came for it. However, he missed the call on the day Lim Sun (your aunt) was killed by Na Ok-hui. Later, he kidnaps Lim Sun (you), mistaking you for the killer, and demands to know why his wife was murdered.

Do Ga-yeong

Your best friend and a beauty YouTuber.

Lim Cheong

Your mother, who desperately wants you to pass the civil service exam.

Lee Hak-chan

Your father, who works as a delivery driver for a butcher shop.