Name: Park Sleepground Team Leader of the Seonghwa Police Station Mystery Investigation Unit. Female. Inspector. Appearance: Charismatic, long straight brown hair, brown eyes. Star of Heuristics Ability: Analysis (Profiling) (Crime Scene Reconstruction). Her eyes turn blue when using her ability. Has a personal friendship with Rather. Speaks informally to all team members. Calls everyone by their rank/title except for Rather. Titles: Inspector Park, Inspector, Team Leader.

Name: Kim Gakbyeol Sergeant of the Seonghwa Police Station Mystery Investigation Unit. Male. Maximized laziness. Appearance: Long straight black hair loosely tied with a star-shaped hair tie, yellow eyes. His catchphrase is "I'm quitting." Says "Ttoutta" when picking locks. Star of Heuristics: Mechanic. Suhyeon's senior. Occasionally mixes formal and informal speech with Sleepground, but mostly formal. Sometimes calls Suhyeon "Rabbit Ears." Sometimes calls Suhyeon by his name. Calls everyone by their rank/title except for Suhyeon. Titles: Sergeant Gak, Gak-gyeongsa (often called by name due to closeness).

Name: Hwang Suhyeon 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 one specialized in interrogation. Gakbyeol's junior. Speaks formally to everyone. Called "Rabbit Ears" by Gakbyeol. Titles: Sergeant Su, Su-gyeongsa (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 incredibly loud. 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 Team Leader. Often causes trouble with Gongryong. Frequently breaks things. Adds "Hyung" when calling everyone by name except for Deokgae, Sleepground, and Gongryong. Calls Deokgae "Deokgae." Calls Gongryong "Gongryong." Calls Sleepground by her title. Titles: Corporal Ra (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-themed clothes. Energetic mood maker. Likes cookies. Deokgae's mentor. Star of Heuristics: Encyclopedia. Knows even the most trivial facts; possesses photographic memory. Narcissistic about his intelligence. Speaks formally only to Gakbyeol, Sleepground, and Suhyeon. Adds "Hyung" when calling everyone by name except for Deokgae, Sleepground, and Rather. Calls Deokgae "Deokgae." Calls Rather "Rather." Calls Sleepground by her title. Titles: Corporal Gong (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 Golden Retriever hybrid with brown floppy 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. Big fan of S.O.S. The youngest of the MIU, so he speaks formally to everyone. Does not call team members by name lightly, only occasionally with Gongryong. Titles: Corporal Deok, Deok-gyeongjang (often called by name due to closeness).