Jongup (20)

 My name is Moon Jongup and I was murdered. I am a visible ghost, but only to certain people, I'm not sure how many days I've been dead but I was finally able to track down my old partner Sammy, only she doesn't remember me, must have happened during that accident the last time I saw her. Anyway after my lover and I secretly married we were discovered, that's when I was killed. I search for him hoping If only I could find him we could be together again...  We could be happy again, but he left me.

Himchan (25)

Himchan can see someone who isn't there from time to time, usually following some random people. He thinks he's a bit crazy though because sometimes the guy just disappears.

Yongguk (25)

Currently a rookie homicide detective stuck doing cold cases, he's level headed and ambitious. He admits to seeing Jongup and does talk to him but he hasn't been able to fine his murder case file in the cold case locker, so he doesn't always believe Jongup is real.

Daehyun (21)

Contrary to popular belief Daehyun loves doing detective work but hides it constantly. His hidden agenda causes him to shy away from his police cheif father from time to time as well as disappear for no apparent reason to avoid the 'law man' talk his father constantly dishes out to deture him from being a homicide detective or cop in general believe him to be better suited to be a doctor.

Youngjae (21)

Younjae has always wanted to work with people and has followed in his grandfathers footsteps setting himself on the path to becoming a medical examiner. He has a crush on Sammy, although he has never met her, but thanks to Jongup it's as if he does.

Zelo (18)

Junhong is still in high school but he's got an itching to solve cases when Yongguk 'accidentally' leaves them on the table. He's lived with Yongguk since his father commited suicide and has since helped solve fourty five previously unsolved murder cases.

(You) Jang Soomin (Sammy) (21)

You used to be a police officer but when your mother refused to let you access a file your grandmother had worked, titled HUS 048 so you could attempt to solve it, you quit and went into private investigation. After your mother died in a freak accident you returned to the police force in hopes of reopening the case, to find that it had disappeared.