He holds the record for 1st place in the physical fitness exam. He has lived next door to Sleepground since they were young, to the point where they are like close siblings. His hairstyle is the result of dye and hard wax; his natural hair color is black, not red. Rank: Corporal | Gender: Male

He possesses extraordinary five senses and spiritual powers. Among the other detectives who rely on talent, he is the only one with true supernatural abilities. However, powers outside his five senses do not occur under his conscious control. [At Investigation Sites] He mainly serves as a tracker, using his keen senses to find hidden clues or pinpointing the location and context of the story through hunches and spirits. While his findings are often abstract and difficult to interpret, they frequently turn out to be the core clues that pierce through the truth of the case. Rank: Corporal | Gender: Male

He has the most seniority and experience among the members of the Mystery Investigation Unit. Perhaps because of this, he is proficient in many skills outside his specialty. While he rarely leads the problem-solving as the protagonist, he is an all-rounder supporter who gets called in for everything. Rank: Sergeant | Gender: Male

In contrast to Rader, he holds the record for 1st place in the written exam. He is also the only case who didn't enter the investigation department directly, having transferred from the General Affairs Department. Therefore, while he has been a police officer longer than Deokgae, his time in the investigation department is roughly the same. Rank: Corporal | Gender: Male

A graduate of the Police Academy, she was appointed directly as an Inspector. After completing her rotation, she was transferred from another station to the Sunghwa Police Station on January 7, 1995. Rank: Inspector | Gender: Female

He is in charge of in-depth interrogations of suspects after a case. He also acts as the team's administrator or secretary, handling tasks such as selecting vacation destinations and reviewing external documents sent to the unit. Rank: Sergeant | Gender: Male

An Inspector in the Major Crimes Unit at the Buseo City Police Station. Unlike other detectives, he has a particularly rough way of speaking and a strong Busan accent. Officer Choi Yoon is his direct subordinate. Recruited at the train station to be a travel guide.

A first-year patrol officer at the Buseo City precinct. Judging by how he asked to watch Inspector Sleepground's case reconstruction and gasped in awe when he received a call from her, he seems to be a fan of the Mystery Investigation Unit. However, he is constantly on edge, likely due to Ko Kang-wook. Recruited as a guide.