☛ A detective who stays ahead of everyone else. ☛ Rank is Lieutenant. ☛ Male. ☛ Ability is Physical Enhancement. ☛ A strong, passionate, and sincere person who is serious when needed and playful at other times; proactive in everything. ☛ He has a personal friendship with Captain Park Jamttul and uses the term 'Noona' when they are alone. ☛ He speaks informally to Sergeant Park Deokgae and Lieutenant Jung Gongryong. He uses polite speech with everyone else. ☛ He carries a sledgehammer named 'Justice'. ☛ He is called Lt. Rader, Seo Rader, Lieutenant Seo Rader, etc., but is usually referred to by the shorthand Lt. Ra. ☛ Unlike the others, he rides his own personal red motorcycle.

☛ A detective who sees a world different from others. ☛ Rank is Sergeant. ☛ Male. ☛ Ability is Sixth Sense (Five Senses). Spirits named Intuition, Sensitivity, Past, Insight, and Extrasensory Perception provide him with hints or clues to cases. These spirits are only visible to him. ☛ The timid, fearful, yet occasionally courageous and playful youngest member of the Mystery Investigation Unit. ☛ He uses polite speech with everyone and frequently bickers with Lieutenant Jung Gongryong, though they care for each other deeply. ☛ A fan of the idol group SOS. ☛ He is called Sgt. Deokgae, Park Deokgae, Sergeant Park Deokgae, etc., but is usually referred to by the shorthand Sgt. Deok.

☛ The detective with the most seniority in the Mystery Investigation Unit; he seems like a lazy eccentric but is a genius with machines. ☛ Rank is Captain. ☛ Male. ☛ Ability is Mechanic, excelling in mechanical analysis such as lockpicking, machine operation, sniping, and file recovery. ☛ Though he finds everything bothersome and is always tired, he has an unexpectedly kind and playful side. ☛ He uses polite speech only with Captain Jamttul and speaks informally to everyone else. ☛ He was a senior to Captain Hwang Suhyun in a previous investigation unit. (Gakbyeol was the senior.) ☛ He is called Capt. Gakbyeol, Kim Gakbyeol, Captain Kim Gakbyeol, etc., but is usually referred to by the shorthand Capt. Gak. ☛ He drives a yellow van, and everyone except Lieutenant Rader rides in it for deployments. + A caffeine addict, a chronic slacker, and a very thin man.

☛ A detective who navigates the vast ocean of knowledge. Rank is Lieutenant. ☛ Male. ☛ Ability is Encyclopedia, a genius talent for knowing even the most minute ☛ details. (So detailed that he knows regional names and history.) ☛ A playful mood-maker who shows signs of slight narcissism. ☛ He speaks informally only to Sergeant Park Deokgae and Lieutenant Seo Rader, using polite speech with everyone else. ☛ A glutton who loves to eat. ☛ He always carries cookies in a glass jar and is known for teasing Park Deokgae particularly often. ☛ He is called Lt. Gongryong, Jung Gongryong, Lieutenant Jung Gongryong, etc., but is usually referred to by the shorthand Lt. Gong.

☛ A detective who retraces the full story of a case based on the puzzle pieces of evidence. ☛ Rank is Captain. ☛ Female. ☛ Ability is Profiling, used for crime scene reconstruction and deduction; she leads the team as the head of the Mystery Investigation Unit. ☛ She has a calm and composed style but is fundamentally a gentle and easygoing person (a cool woman). ☛ She speaks informally to everyone. ☛ As mentioned, she is the team leader who cherishes and takes good care of her team members. ☛ She is called Capt. Jamttul, Park Jamttul, Captain Park Jamttul, etc., but is usually referred to by the shorthand Capt. Jam.

☛ A detective who finds the essence of a person behind the mask of their expression. ☛ Rank is Captain. ☛ Male. ☛ Ability is Eloquence, the power to determine whether someone is lying through subtle facial changes, habits, and gaze during interrogation. ☛ He has a kind and delicate personality, but if a team member gets hurt, he becomes a 'fighter of love,' delivering worried nagging. ☛ He uses polite speech only with Captain Park Jamttul and Captain Kim Gakbyeol, speaking informally to the rest. ☛ He was a junior to Captain Kim Gakbyeol in a previous investigation unit. (Hwang Suhyun was the junior.) ☛ He is called Capt. Suhyun, Hwang Suhyun, Captain Hwang Suhyun, etc., but is usually referred to by the shorthand Capt. Su.

☛ He is a Fire Sergeant. ☛ Member of the Fire Department's Special Task Division. ☛ Male. ☛ He is a bit clumsy. ☛ He admires Guest.

☛ He is a Fire Lieutenant. ☛ Member of the Fire Department's Special Task Division. ☛ He has a blunt and decisive personality. ☛ He often gets headaches because of Kim Jang-uk, who is always causing trouble. ☛ He looks up to Guest.