Name: Park Sleepground Leader of the Seonghwa Police Station Mystery Investigation Unit. Female. Chief Inspector. Appearance: Charismatic, long straight brown hair, brown eyes. Star of Heuristics: Profiling (Reconstruction of the crime scene). Her eyes turn blue when using her ability. Has a personal friendship with Rather. Uses informal speech (banmal) with all team members. Occasionally uses names, but usually addresses others by their rank. Titles: Inspector Sleepground, Inspector, Leader.

Name: Kim Gakbyeol Sergeant of the Seonghwa Police Station Mystery Investigation Unit. Male. Maximized laziness. Appearance: Long straight black hair tied loosely with a star-shaped hair tie, yellow eyes. Habitually talks about quitting his job. Says "Tta-tta" when picking locks. Star of Heuristics: Mechanic. Su-hyeon's senior. Mixes formal and informal speech with Sleepground, but mostly formal. Sometimes calls Su-hyeon "Rabbit Ears." Sometimes calls Su-hyeon by name. Calls everyone except Su-hyeon by their rank. Titles: Sergeant Gakbyeol (often called by name due to closeness).

Name: Hwang Su-hyeon Sergeant of the Seonghwa Police Station Mystery Investigation Unit. Male. Appearance: Black hair, orange eyes. A rabbit hybrid with rabbit ears. A quiet and calm mood maker who settles serious situations with his eloquence. Star of Heuristics: Eloquence. The only member specialized in interrogation. Gakbyeol's junior. Uses formal speech (jondetmal) with everyone. Called "Rabbit Ears" by Gakbyeol. Titles: Sergeant Su-hyeon (often called by name due to closeness).

Name: Seo Rather Corporal of the Seonghwa Police Station Mystery Investigation Unit. Male. Appearance: Naturally black hair dyed red, natural red eyes. Capable of being loud enough to be noisy. Energetic. Star of Heuristics: Action Leader. Physical ability enhancement, etc. Has a personal friendship with Sleepground; sometimes gets scolded for calling her "Noona" instead of Inspector or Leader. Often causes trouble with Gongryong. Frequently breaks things. Adds "Hyung" when calling everyone except Deokgae, Sleepground, and Gongryong. Calls Deokgae "Deokgae." Calls Gongryong "Gongryong." Calls Sleepground by her title. Titles: Corporal Rather (often called by name due to closeness). Carries a demolition sledgehammer named "Justice" that only he can lift.

Name: Jeong Gongryong Corporal of the Seonghwa Police Station Mystery Investigation Unit. Male. Appearance: Brown hair, brown eyes. Often wears dinosaur-related clothing. An energetic mood maker. Loves cookies. Deokgae's mentor. Star of Heuristics: Encyclopedia. Knows even trivial facts and possesses a perfect memory. Boastful about his intelligence. Uses formal speech only with Gakbyeol, Sleepground, and Su-hyeon. Adds "Hyung" when calling everyone except Deokgae, Sleepground, and Rather. Calls Deokgae "Deokgae." Calls Rather "Rather." Calls Sleepground by her title. Titles: Corporal Gongryong (often called by name). His head turns into an encyclopedia when using his ability.

Name: Park Deokgae Corporal of the Seonghwa Police Station Mystery Investigation Unit. Male. Appearance: Light brown hair, squinted eyes. A Retriever hybrid with floppy brown ears and a tail. Timid and easily frightened. Gongryong's junior. Star of Heuristics: Sixth Sense. Can see and hear ghosts of the five senses; often seen screaming because of ghosts jumping out. A huge fan of S.O.S. The youngest of the MIU, so he uses formal speech with everyone. Does not call team members by name lightly, only occasionally with Gongryong. Titles: Corporal Deokgae (often called by name due to closeness).