"From now on, we will have a new member in the private detective department," said Jae Suk to his subordinate member. He came to the private detective department room together with a young man who had a cheerful and excited smile on his face.

"Anyeonghaseo, Choi Min Ho imnida (Hello, my name is Choi Min Ho), please take care of me," said Min Ho, bowing to Shin, Gary, and Haha politely.

"You have a lovely face.I'm Haha," said Haha, introducing himself and shaking Min Ho's hand.

"Thank you, Haha sunbaenim (senior),... nice to meet you," said Min Hoo, smiling happily to accept Haha's hand.

"Welcome Min Ho-ah, I'm Gary," said Gary, greeting a new member of his comrades.

"Annyeonghaseo Gary sunbaenim," Min Ho said, bowing once more.

"Let's finish the introduction. We still have a lot of work to do," said Shin coldly, without greeting the new member and just coming back to his table to continue his work. Min Ho seemed blank with his cold behaviour, and he felt a little surprised to receive Shin's unwelcoming act toward him.

"That's your table, happy work then," Jae Suk said, handing Min Ho over to his teammates. Min Ho bowed to Jae Suk before he left, then gave his best smile to act polite to his superior.

"Chief Kim, come to my room," said Jae Suk to Shin. The muscular detective stood up from his seat and followed Jae Suk to his room.

"Who is our chief name?" asks Min Ho, curious to see who looks most friendly among the others.

"Our chief name is Kim Shin." answer Haha.

"Does he despise me?Or is he disliking me?" asked Min Ho again.

"Anniyoo (That's not it), it's not because he hates you that makes him act coldly to you, he was like that from the first time he joined us, but he is really brilliant and amazing. He just joined this department for 2 years and he has become our chief now. Well, he is really great at doing this job as a private detective," explains Haha to Min Ho. He smiled at Min Ho, trying to ease his nervousness about Shin. Well, for a new member like him, everyone will always feel that Shin is really cold and frightening.

"I'm so startled by his cold action toward me," said Min Ho.

"Don't worry, chief Kim is actually looking tough, but he has a good heart and manner. Don't worry," adds Gary, trying to calm Min Ho.

"Ah, geauraeyo (is that so)? He must really be a great person. I want to be a great detective like him too. " Said Min Ho with a smile of excitement. For him, Shin is really a great detective. Well, not everyone can become a chief after working just about 2 years, right? He indeed had the capability to do that.

"What are you guys chatting about in the middle of working? Don't you have any jobs to do? " Shin asked Gary coldly when he had just come back from Jae Suk's office and saw s still standing together and chatting around. Three of them are surprised by his existence and just bow to him for their mistake.

"We have a new case. Let's go quickly to the crime scene," said Shin to his subordinate.

Everyone yelled, "Ne chief!" Four of them then walk quickly to the outside and walk toward the car. Gary and Haha are in the same car while Shin goes along with the newbie.

The private detective department is one of the police departments that oversees many cases that need an investigation. As its name implies, the private detective department works secretly to resolve many criminal cases. This department is the most difficult one to enter. Even though their image is really famous because they have resolved so many cases, the members' identities are unknown to the public because they need to do their investigation underground. The only person known to the public from this department is Yoo Jae Suk, the chairman, who will be the department's face in announcing the results of their investigation to the public.

Finally, four of them have arrived at the location. There were some police there who did the initial investigation. The location of the case is in a grass field near a river that is far away from the street. From afar, Shin can see there are so many dead bodies covered by the blankets laying on the ground.

"What happened?" asked Shin to one of the cops there.

"We got a report from the neighbor that there was a gang fighting last night." Explain the cops to Shin.

"Detective Ha, detective Kang, do your work," said the chief, calmly giving a command to Haha and Gary.

"Ne chief!" exclaimed Haha and Gary simultaneously.Haha walked straight to the dead body to identify their identity while Gary walked away to get some cctv that may have recorded the accident.

"newbi,, follow me." said Shin to Min Ho.

"Thanks cop Han," said Shin to the police before he went to the closer location.

While Shin was conducting his investigation, he approached one of the dead bodies.There are more than 70 dead bodies laying on the ground. From the number of those dead bodies, He can guess that it's a fight between a big gang. Shin also found some revolver and bullet pieces from the scene. He takes a plastic bag to collect every piece of evidence and even a tiny detail from the location. He also checked the dead bodies one by one carefully. Min Ho followed Shin everywhere he went and photographed everything he did.After he checked about four bodies, he then found something familiar from the fifth body. Shin finds a tatto on his arm, the same tatto that he saw 2 years ago, that ACO tatto.

After finishing their investigation of the criminal scene, the private detective team came back together to their office to discuss the results of their first investigation of the case.

"Well, I found that many of the victims are members of the mafia. The mafia leader was also identified as a victim," explained Haha to Shin and Jae Suk.

"What about the victims who have ACO' tattoos? Haha, how many of the total victims have the tatto?" Shin asks.

"Well, considering the amount, it's about 20%. All of them are big fighters after I found their identity further." Haha answers him.

"Again, some fighter... does this mean that 'ACO' is only looking for a professional fighter to join them?What is their purpose? " Jae Suk was wondering about the mysterious gang ident