"Hello Angels. Welcome to another deadly mission." Chan Shik, their head supervisor handed each one of the six Angels a file. "In those file, you will see six members of Exo-K." He continued.

"I've heard about them." One of the Angels replied while her hands actively flipped through the next page. 

"What about them?" Eun Ae, another Angels, just stick her eyes to Chan Shik instead of looking through the file. Uninterested until she knew what the mission is all about. 

"It better be not about stalker." Haeun, the leader among the angels raised her eyebrow while looking at her head supervisor. 

"Threatened by the Dark Devil?" Hanyoung looked up to Chan Shik after finished reading the file. 

Dark Devil. The name itself tells you how merciless they are. A lot of lives has been killed by them. A lot of innocent people were killed by them. You wouldn't know who they are. You might not know that the member that is next to you while you were shopping, might be one of the Dark Devil members. They are everywhere, but they are professional Assassins who never get caught. Not even once. 

"One point goes to you for reading the file thoroughly." Chan Shik pointed at Hanyoung. "And yes, these young idols are being threatened by Dark Devil. They don't know who did that though, but on the dorm's door, there are Dark Devil's symbol which none of them are aware." 

"Of course they are not aware. Dark Devil don't just put their signature that obvious." Haeun muttered and still flipping through the pages. 

"As we know, how violent Dark Devil is, we have to protect this idols before any lives fly away again." Chan Shik seriously looked at each of the Angels. 

"How?" The third unknown Angel asked while looking at him. 

"As usual, it's time for undercover, Angels!"