Shim Changmin a renowned detective goes on a mission to solve the mystery of the missing black opal with his slaves minions apprentices Kim Jaejoong and Jung Yunho. 

Kim Jaejoong : 23 year old, Changmin's apprentice, Cunning and manipulative

Jung Yunho : 23 year old, Changmin's apprentice, Knows Hapkiddo

Shim Changmin : 21 year old, Owner of his detective firm 

Kim Junsu : 22 year old, Suspect, Suffering from a psychology disorder

Park Yoochun : 22 year old, Owner of the bank the Black Opal was kept