On a saturday night,usually people would go out with their friends and have fun but for a certain girl,she would rather stay in her office with paperworks as her company.Cho Aeri,a 23 years old police officer.It might sound weird but she loves doing her job.A job where you have to be brave to save the world and she is brave enough.

Because of her concentration on those paperworks,she did not heard the door opened.Only when a certain "Ehem" startled her and made her look up from the papers."Ah Officer Shim,what are you doing here at this hour?" Aeri aked.Officer Shim,a 25 years old pollice officer.He was said to be the best at using the gun and aiming an oneshot kill.And also , he is said to Aeri's current lover but was denied by her."I was out with some friends.Thought I come by to say hello" He said while taking a seat infront of Aeri's desk."Oh and call me Changmin.Officer Shim sounds too formal" He smiled his oh-so-famous smile that can melt any women's heart.

Julia smiled."You never change do you ? " She playfully shakes her head and went back to her work."Well I'm not the only one.You're still the same girl I used to know.A workaholic" Somehow,that made Aeri smile."Well nice to know that" and Changmin smiled a little. "You are always diligent on doing your job.That's what I like the most about you" A high-ranked pollice officer is praising her for her hardwork.She felt proud."Well thank you,Officer Shim.I will work harder" Another smile.

She almost let out a curse when she saw the watch on her office wall.It was late and she needs to go home."I'm sorry but I need to go now" In a haste,she quickly packs her stuffs and bowed to the officer."Let me send you home" He quickly said."It's okay,maybe next time.Goodnight Officer" And just like that,she was out of the room and Changmin was left alone."You are always acting like this.Am I not good enough for you? " He said to nobody.With a sigh,he got up from the chair and went out of the door.

"Good Morning everyone" The girl greeted everyone in the room as usual."Good Morning,Aeri.Early as usual" Officer Yoo Youngjae greeted her with a smile."Thank you" She shyly smiled and went to her office."oh yeah,Chief Choi wants to see you in his office" Youngjae said and went back to his work. 'Chief Choi?what does he wants at a time like this?' Aeri thought as she walks to Chief Choi's office.With a deep breath,she went inside the room.There sat Chief CHoi himself and Officer Shim.Oh. 

"Officer Cho ! Just in time.Come sit" Chief Choi or as people call him,Siwon,pulled the chair for her."Thank you.You didn't have too" She sat and tucked a fallen hair behind her left ear.'She's embarrassed.How cute' Changmin thought.He was looking at her face.Fair cheeks with a tint of red crimson colour.Beautiful eyes that sparkle.A cute nose and lips.Thin lips.A small cough from Siwon startled him from his day dreaming.

"So I called you guys here today because I have a really important task to give out" Siwon pulled out a file from one of the file lockers.The file was stamped "PRIVATE" with red ink."He's back" He said.Which confused both Changmin and Aeri."I beg your pardon,Sir ?" Aeri said. "The serial killer or is known as the 'Black Devil' " Siwon looked straight into Aeri's eyes.Siwon noticed a hint of fear in her beautiful brown eyes."Don't worry,Aeri.Officer Shim here will be with you in this investigation" Siwon turned his attention to Changmin.He didn't say anything but by the look of his hyung's face,Changmin knows what he wants to say. 'I can trust you on this right ?' Changmin replied with a small nod."Well then,here's the file.Officer Shim and Officer Cho,you are now officially included in this investigation.Good luck." He gave them the file and dismissed them both with a smile.

Inside Aeri's office,they began looking at the file."so where should we look first ?" Aeri asked."hmmm,where do you think we should go first ?" Changmin eyed her."I think we should go to this old abandoned building.It was said that he is last seen there.What do you think ? " Changmin thoughted for a moment."Good idea.Let's go" 

And so,the investigation begins.