"Oppa! Guess what, guess what??"

Youngho looked up from his documents uninterestedly to see his younger sister jumping around while holding an envelope.

"What, Yerim? I'm currently stuck in a difficult case," he grumbled.

"Aren't you always?" Yerim snickered.

Youngho chuckled, giving in to his sister, "Alright, alright. What is it?"

Yerim grinned before fishing a piece of paper and shoving it to Youngho's face. "Tadaah! I'm being moved to your station! From now on I'll be able to see you at work every day! Yay!"

Youngho gaped before snatching the paper from her. He blinked his eyes and it was correct. Yerim received a promotion from the forensic department in Jongno-gu to Yongdeungpo-gu.

"Whaaat? Sis!" Youngho laughed before pulling the girl into a hug.

Yerim giggled into his chest, "I know. Supposedly your precinct needs my help on my medicinal knowledge. I'm not really sure myself, but Joohyun unnie's husband was the one who requested the transfer."

"Chief Kim?" Youngho pulled away.

"Yep. Chief Kim Joonmyun said there's a potential serial killer and he needs someone with medicinal knowledge and doubling as a forensic analyst since one of the workers left due to marriage if I'm not mistaken. And then Joohyun unnie recommended me to him," Yerim shrugged.

Youngho nodded. It makes sense. Their current forensic doctor, Dr. Do, works alone since his partner Dr. Park moved to Daejeon after getting married. With the alarming amount of cases they've been getting, they definitely need a new forensic specialist. There aren't that many cases in Jongno-gu according to Yerim, maybe that's why she got transferred.

"When will you be working then?"

Yerim grinned, "Tomorrow! Chief Kim said he will introduce me to the detectives I'll be assisting. I think they're gonna be one of your friends. How many detectives are there?"

Youngho shrugged, "There are two teams. I led team 1, with my friend Jay and Doyoung. Team 2 is led by Taeyong, consisting of Jungwoo. Maybe you'll work with Taeyong."

Yerim shrugged, "I was hoping I'll work with you; you know."

"And have you annoyed the out of me 24/7? Whee. Fun," Youngho commented dryly.

Yerim punched his brother for his sarcastic remarks, "Yah! I'll tell mom!"

___ 

Yerim entered the precinct nervously. She was directed to go to the forensic room which was on the basement. She knocked the glass door twice before entering, instantly face to face with a short male using thick rimmed glasses.

"You must be the new forensic specialist?"

Yerim bowed, "Ah, yes, I'm Dr. Kim Yerim. Nice to meet you…"

"Do Kyungsoo."

"Nice to meet you, Dr. Do. I'll work hard, please take care of me," she bowed.

The man smiled, "Come sit down. Joonmyun will be here any second."

The guy directed her to his office, passing the morgue on their way there.

"Is that the morgue?"

"You guessed that right. Come, this is my office. Take a seat. Your new office will be next door."

She nodded and hesitantly sat down on the couch. Not long after that, the door opened, revealing a familiar man.

"Oh, Yerim-ah, you're here."

"Chief Kim," she bowed respectfully.

"Hyungnim."

Joonmyun brushed off Dr. Do casually as the three of them sat down. "So, I think both of you are quite surprised with the sudden transfer. As you know, Dr. Park transferred to Daejeon for marriage and we still haven't got a replacement yet. And then the Medicine Murder case is getting bigger too, so we need someone with extensive knowledge in drugs to help us. Joohyun recommended me you, and I consulted Seulgi as well, and contacted your superior in Jongno. Everyone seemed to acknowledge your talent, that's why I requested for your transfer."

"Ah, thank you very much, Chief."

"Anyways, the case that has been bugging us for the past two months is called the Medicine Murder. It is currently being taken care of by our homicide detectives, but it seemed like it was a meticulously planned murder since the body was always sent to one particular detective in this precinct. Dr. Do can brief you about the past two bodies that had come before, but first I'd like to introduce you to the team that handled this case. Let's go upstairs and I'll bring you to them."

Yerim nodded dutifully before standing up. She bowed at Dr. Do and bid goodbye before following Chief Kim outside towards the elevator.

"So, Chief, the murderer... has some problem with your detective? Why did he send the bodies to him?" Yerim asked curiously inside the elevator.

Joonmyun shrugged, "That… baffled us as well. That detective of ours has a clean record, graduated from the academy with honors, and has a brilliant case-solving record. It's weird. See him and make your own judgement. I used to be his team leader so I knew him pretty well."

Yerim nodded as the elevator stopped.

"Come."

She excitedly followed him. She hoped she'll come across her brother there.

"This is my office. The detectives are probably in the meeting room discussing the case. I'll call them here. Sit down."

Yerim nodded and sat down on the couch, fiddling with the sleeves of her white coat nervously. Is this going to be the Lee Taeyong?

"Chief!" A tall guy with brown hair entered the room with a smile.

"Jay, sit down. Where's the other?"

"Ah, still meddling with the murder board, making up theories. The usual. They’ll be here shortly."

"Oh, okay. This is Dr. Kim, the one I told you earlier this morning."

"Oh, the new forensic? Hi, I'm Jung Jaehyun. Or Jay," the man smiled, his dimples showing.

"I'm Kim Yerim. Nice to me—"

"Chief! Sorry, we're late! We were—Yerim?!"

Yerim nearly jumped from her seat when she saw her brother entering the room.

"Oh, oppa!"

Chief Kim and Jaehyun exchanged confused glances as another guy entered the room while panting.

"Ya! Johnny! Wait!"

"You guys know each other?" Jaehyun blinked curiously.

"Yeah. She's my half-sister. Why?" Youngho answered casually as he plopped down next to her, mussing her hair in the process which earned him a cute grumble from the short lady.

"Great! I can skip the awkward introduction phase then! Johnny, this is Yerim—you know your sister, not surprising. And I think I forgot to tell you. I did tell Jay though. She's the drug specialist and new forensic staff that will assist you in the Medicine Murder case!" Chief Kim grinned.

"She—what? Chief!"

Yerim blinked as she watched her brother bickered with his chief. She's a bit hurt because it seems like her brother doesn't want to work with her but it's not like she can in into their arguments either.

"Detective Seo, go the meeting room and brief her. And oh, introduce her to your other two friends here. I got paper works to do. Now shoo! Off you go, out of my office, all of you!" Chief Kim chased them out with a fly swatter and the four people had no choice but leave.

Youngho grunted as he briskly walked away. The case he's working on is nasty. And he's the main target of the murderer's taunts. The last thing he wants is to involve his beloved baby sister.

"So, you and John are siblings? I mean no offense, you guys don't look exactly similar," the unknown guy chirped.

"Uhm, half siblings, actually. We have the same mother, but different fathers," Yerim answered.

The guy grinned. "I'm Doyoung. Your brother's friend. And that cool potato there, is Jaehyun. Or Jay. Your brother's loyal sidekick."

Yerim nodded in interest as they entered the meeting room. She glanced at a fully loaded lead board with pictures of bodies in it along with information.

"When you told me that you'll be moving here last night, I thought you'll be assigned to Taeyong's team," Youngho spoke up as he sat down in a chair next to Yerim.

"I just found out this morning too. Why is it? Are you looking down on me?" Yerim eyed him and he rolled his eyes.

"Oh, please. I know how great you are. But it's just… dangerous. So, I'm… a bit restless."

"How sweet of you. Never seen him like this," Doyoung grinned, earning a pen thrown into his direction from Youngho.

Jaehyun sat down silently as he studied the siblings. He could clearly see how much Youngho loves his sister. And he could see his sister is one stubborn soul. It's intriguing, really.

"Anyways, we still need to brief her. Chief's order," Jaehyun spoke up.

"Fine, fine," Youngho groaned before standing up. Yerim swung her feet as she watched her brother moved near the murder board.

"So. Medicine murder. 2 bodies in a span of two months. All bodies died due to specific reasons triggered by medicine. This one is Shin Yunho. 24 years old college students. He’s taking a master course in engineering major. Estimated death time at 10 p.m. Cause of death according to Dr. Do is asphyxiation."

"There were no strangulation marks. Covered with pillow or something?" Yerim mumbled as she examined the picture closely. The body looks like it has started the decaying process.

"Nice guess, but no. He had Bisoprolol overdoses."

"Bisoprolol? That's a non-selective beta blocker. Affected not only the heart but also the beta receptors in the airway. May caused bronchospasm. Bisoprolol is intended for patients with cardiovascular disease. 24 years old seems too young to be consuming CVS medications," Yerim raised her brows as she rambled incoherently, mainly to herself.

"That's why it's classified as murder."

"So, cause of death is bronchospasm?"

"We suspected that's not the main cause of death even though it might make dying a bit easier. But he was shipped to this precinct and we didn't have a crime scene to investigate so CSI and forensic are a bit unsure. Maybe you can go check the body again later with Dr. Do," Youngho explained.

"Okay… But oppa, his joints… seems a little funny. He had a broken bone as well?"

"That…. Jay? Can you take over? I'll pitch in but I need to finish this report first," Youngho asked as he sat down to finish whatever he's writing that he left unattended when Chief called him moments ago. Jaehyun cleared his throat,

"Each victim are folded into a blue cardboard box, shipped directly to this precinct. The act of folding a body into a box required solutions to fit the body in. The murderer acquired it by breaking the bones and joints."

"Oh, wow," Yerim gulped.

"Well, shall we move to the next victim?"

"Yeah, yeah, sure."

Jaehyun moved to the right side of the board. "Sung Yoonhye. 26 years old. Any interesting marks except the broken bones?" Jaehyun playfully challenged her.

"The body looks pretty decayed, like the previous one. Maybe four or five days? It's hard to determine without getting hands on," Yerim peered on the pictures carefully.

Jaehyun smiled. His observation is proven true. Yerim is one bright kid with a knack in forensic. Youngho's family is truly blessed with genius brains.

"Correct. Dr. Do predicted the body had decayed for five days when it arrived here. Anything you can deduce though?"

"Wow, are we grilling her?" Doyoung grinned from his spot.

"Go on Jay, this little tweety could have a little test before joining the squad," Youngho piped in as he cackled evilly, earning a glare from Yerim. Jaehyun examined them closely, they looked close to each other and they have a healthy brother sister relationship.

"Well, the lips are bluish…. dark color? It could have been due to hypoxia. Central hypoxia."

"Whoa… she's smart," Doyoung commented.

"Oh, I'm right?" Yerim turned her head and the guy gave her a thumbs up.

"Great job, sissy," Youngho grinned before going back to his report.

"Victim died due to cardiac arrest. Dr. Do said he found an alarming amount of Captopril in the patient's system."

"Another CVS medication? A human can take up to 100 mg of captopril daily, but that's for patients with diabetic nephropathy and a 26 years old girl doesn't seem to suffer from it," Yerim scratched her head.

Jaehyun read some of Dr. Do's note on the board before nodding. "Dr. Do predicted that the patient had at least 200 mg of captopril in her body."

"Now that's lethal," Yerim nodded.

"We were torn between two theories: a serial killer doing or a copycat murder. But both bodies are treated the same. Decayed for days, folded, and stuffed into a cardboard box, tied with ribbons, sent here specifically to Johnny," Jaehyun shrugged.

"And… they both died due medicinal use. CVS medication to be exact. That is enough leads to point it out as a related murder," Youngho nodded.

"That's interesting. Maybe later I could go back down and ask Dr. Do about the body. He seemed like a cool guy."

"Dr. Do is as cool as a cucumber. Pretty stoic, but effective in his work and incredibly talented too. It'll be a great opportunity for you to be his apprentice," Youngho smiled kindly at his sister, the small act doesn't go unnoticed by the ever observant Jaehyun.

Yerim was about to open when someone barged in, panting, while holding the door handle.

"Detective Seo!"

"Jungwoo, calm down, what's wrong? Need help? Where's Taeyong?" Youngho asked calmly.

"No, no. There's another package sent for you…. The blue box one."

"Oh, ."

___

Yerim ran along, trying to catch up with the three giraffes that bolted out at the speed of light.

"Wow, so much of welcoming me into their squad," Yerim rolled her eyes as she approached a commotion.

A strong scent could be smelled from a far. Stinky smell. Yerim could see her brother looking furious and depressed at the same time, judging from his expression and the tightening of his jaw. Jaehyun looked stoic as ever, and Doyoung looked comical almost with his mouth gaping. She approached the commotion, and thankfully Jaehyun spotted her.

"Wanna take a look?" He asked gently, observing Yerim's face closely.

The girl nodded confidently before stepping forward, standing next to her brother.

"Rim…"

"I'm okay, oppa. I deal with this all the time," she shrugged casually as she examined the nasty thing in front of her.

A body of a man, twisted and folded certain ways inside a blue cardboard box. A black ribbon tied on each of his wrists. There was blood everywhere and nasty traumas on his bodies. Quite different from the pictures she saw in the meeting room.

"The body's beginning to decay. If I should take an educated guess…. Four days. Hence the smell and the maggots," Yerim said with a grimace.

Jaehyun nodded his head. Yerim knew a lot for her age.

"I'll contact CSI and asked them to bring the body to the morgue," Doyoung said before ushering other officers to leave the scene.

Chief Kim appeared from his office looking distraught. "Another body?"

"Yes, chief. We were correct. It was a pattern. Once every month," Jaehyun spoke up.

"Call the CSI, bring the body to the morgue to Dr. Do. Oh, there's Dr. Kim as well. Your first body, Yerim. Please help Dr. Do investigate," he ordered.

"I've called the CSI, chief," Doyoung said.

"Alright, shall we go to the morgue then?" Youngho sighed dejectedly.

CSI came to investigate and relocated the body to the morgue. Doyoung stayed back to supervise while Youngho and Jaehyun headed to the morgue alongside with Yerim.

"Dr. Do," Youngho bowed as he entered the morgue.

"Detective Seo. What's wrong? Needed another testimony?" The forensic doctor asked.

"No, Doc. We… actually had a new body sent to me this morning. Maybe you can investigate it... with my sister here. It's not her first but well… first of this case," Youngho explained.

"Oh, Dr. Kim is your sister?"

"Yes."

"Okay, we'll get right through it. Dr. Kim? Follow me."

Yerim gave her brother a small hug before following Dr. Do. Jaehyun found their interaction quite endearing. He knew the sudden body disposal at Johnny's desk had shaken up the man, but he still took time to care for his sister. They both turned around to see the CSI team carrying the body and bringing it to the metal table where Yerim and Dr. Do awaited.

"No clues about the sender, just like the last time," the CSI guy informed to Jaehyun.

"Thanks, officer Lee." Jaehyun followed Youngho to approach the table where the body is laid on.

"Since I have an assistant, result may come a bit faster. I'll try to have the report out after lunch," Dr. Do informed.

"Thank you so much, Dr. Do."

"Or, you know what? I'll have Dr. Kim informed you once in a while too so you can start on the lead board. You can go back to your office, Detective Seo, Detective Jung."

Youngho turned to his sister who smiled softly at him, giving him a secret fist pump. He smiled at her, muttering a good luck, before leaving with Jaehyun.

"Shall we get to work, Dr. Kim?"

"Yes, Dr. Do!"