Choi Seung Hyun aka TOP: A guy who never forgets a friend. He’s been working as a transporter for awhile now. He’s 22 year old guy who’s not married, not dating, or looking for anything. He’s just more into his job than girls. Well, that’s what everyone thinks. One day when his friend was put into jail due to a murder his friend didn’t do, he takes on the case and helps him out, even though his friend is a gangster from the gang IRIS. Every cop has been trying to track down these IRIS people, and Seung Hyun knew it’s his chance to do so. As a transporter, no one knows that Seung Hyun is can also be such a secretive assassin too. Seung Hyun then deals with another gang that has wanted to kill these IRIS gang. This gang is called SHIRI, and they want to haunt down IRIS. So Seung Hyun makes a deal with SHIRI to eliminate IRIS and they help him get Ji Yong out. Being protective, he tells one his girl friends who he’s really close with, Sandara Park, to hideaway with his stepbrother Park Jungmin, because he has a feeling Dara will be involved, as she witnessed the death of her brother’s. Will everything go successfully? What about the mysterious man who’s targeting Seung Hyun’s stepbrother? How will Seung Hyun save his step brother and help Ji Yong?

Kim Junsu aka Xiah: The son of the IRIS gang leader takes his job seriously. Age 23, single, not married or dating, but goes to the club once in a while to get his needs. To impress his father and wanting to take after his father’s spot after his father dies, Junsu uses one of his good friend to murder this guy who’s best buds with one of their gang member, Kwon Ji Yong aka G-Dragon. Junsu hated his father for favoring Ji Yong for being a great gang member and shall make him gang leader. So Junsu purposely puts his father into the hospital, and blames it on Ji Yong. Not just that, Junsu’s men killed one of Ji Yong’s best friends. The police got Ji Yong as Junsu is happy and pays his friend for what his friend did. Couple days later, Junsu receives a call about half his men and his father’s people dead in China. Junsu freaks out and wonders who had done this. Then he was told by his cousin, Kim Hyun Joong, that the best friend of Kwon Ji Yong they killed was not someone who Junsu thought it was. Now the person is looking to haunt him down through Junsu’s own friend, Kim Jaejoong aka Hero. Hyun Joong promised Junsu that, if he kills the guy, Hyun Joong gets the head to be called leader. Now will Junsu really be a good leader after for IRIS? What will happen to Junsu? Does he think everything was easily done?

Kim Jaejoong aka Hero: Just a friend of Kim Junsu, who happens to did one thing for money. Murder. At the age of 17, his mother started sleeping more and more in the hospital. The bills rise higher and higher. Now at the age of 24, Jaejoong is working hard to pay it all off until one day, his old high school friend Junsu came to him for a favor. Kill a dude and he gets the money that will pay off his mother’s hospital bills. Jaejoong’s life has always lived as a poor, Junsu was always there to help him, and now Junsu wants a murder done. Jaejoong couldn’t say no, Junsu was there too much for him. Jaejoong takes the offer, but not as an offer of being part of IRIS, but killing the guy he was ordered. Jaejoong doesn’t know why, since Junsu doesn’t tell Jaejoong the reason, but Jaejoong needed money and so he killed an innocent guy and flees. What he didn’t know is that, when he killed the guy, it was a wrong guy. Also, there was someone who witnessed him before he fled. Jaejoong didn’t care, cops weren’t looking for him, and so he thought he was safe. Suddenly, after visiting his mother at the hospital one day, one of his working buds told him about some thugs looking for him. Jaejoong didn’t know who they were, but he’s going to face them if they were going to look for trouble. Gunshots were heard before this, and Jaejoong then stepped out. Indeed they looked for trouble, but they weren’t ordinary men. Jaejoong recognized them immediately. SHIRI gang members came looking for him. Just as he thought he was safe by Junsu’s words, SHIRI came and beat him into a pulp. Now what do you think Jaejoong will do? What will happen between him and Junsu’s friendship?

Kwon Ji Yong aka G-Dragon: A guy who involved himself in a gang called IRIS. At first everything was going cool for this 21 year old guy who is very much single, but a womanizer you can say. Until his life came tumbling down when his best friend’s brother got shot and killed. Ji Yong was confused about all these commotion ever since he was kicked out of IRIS. Ji Yong was framed for putting his boss in the hospital, and now his best friend’s brother dies? Something was going on and he didn’t know what to do. Sandara Park was the one who he decided to visits, and finds her brother dead. He pushes her out of her apartment and tells her to runaway and looks for Seung Hyun and tells Seung Hyun about this. Ji Yong pushes her out as he hears the cops coming already. How can someone just die so fast and the cops already know? Questions ran through Jiyong’s head and he can’t figure out what to do. He makes a run as he puts blood on his body, so the cops won’t chase after Dara. Unluckily, he gets caught and puts to jail. Wishing everyday in prison that he didn’t get caught or wishing that he never joined IRIS. He was always stubborn and didn’t listen to Seung Hyun’s words. Now he’s locked up. Couple weeks later, he was let out and he found Dara and Jungmin there. Ji Yong was happy to see his friends, but what got him thinking is, where’s Seung Hyun? Also, how did he get release when Dara and Jungmin received a call to pick him up only?

Sandara Park aka Dara: A sweet girl at the age of 25, not married or dating, but is best friends with Choi Seung Hyun, Kwon Ji Yong, and Park Jung Min. Has a younger brother, Sang Hyun Park, aka Cheondung/Thunder. Her neighbor her friends, everyone and everything were sweet. Until one day when Dara’s brother Cheondung was making lunch for her and her friends, there was a gunshot heard in the kitchen. Dara rushes out of the bathroom and found the killer leaving the apartment as her brother is dead on the floor. She cries and is shocked that her brother is dead. Ji Yong then pops up by the door and sees her. Ji Yong pushes Dara away and tells Dara to call Seung Hyun and move away as the cops are coming. Dara does what she’s told, and when she reached a phone booth, she immediately calls Seung Hyun and tells Seung Hyun that Ji Yong is caught due to the gang IRIS. Seung Hyun angrily yells and tells Dara to go in on a hideout with Jung Min for some days as he handles some stuff. Dara agrees and leaves with Jung Min after her brother’s burial. Will Dara think of revenge?

Kim Hyun Joong: The cousin of Kim Junsu. A 24 year old dude which to him, everything is a game. He played with girls hearts, and kill people for fun. He thinks everything to him is a game ever since his uncle killed his dad. Hyun Joong’s father was the leader until his uncle; Kim Junsu’s father killed him. Hyun Joong was the only one, only person who saw the murder. No one would believe a thing Hyun Joong said, since Hyun Joong was only 11 years old back then. Hyun Joong is a sneaky guy, and he found Junsu being fishy one day being jealous about a regular member being favored by the boss. Hyun Joong watches Junsu’s every more and one day caught Junsu in his own trap. Junsu is freaking out and needs help more than ever. Hyun Joong has a plan even though it’s not that great. He’s a man who people randomly hire to kill person for them, and he gets paid. So one day while he checks his mail, he found his new target, which leads to a man his cousin Junsu wants dead. Hyun Joong then goes to Junsu and tells him that if he wants the guy dead, Junsu will have to give up the leader spot. Now will Junsu listen to Hyun Joong? Will everything go as Hyun Joong plans?

Park Jung Min: The step brother of Choi Seung Hyun. A 23 year old guy who was once engaged to a beautiful woman named, Lee Seung Hee. After she was murdered in front of his eyes, he swore he’d find the killer and kills this person two times worse how his fiancée was shot and killed. A guy offers Jung Min a job, since he knew a little about Jung Min’s problem. Jung Min refuses and leaves the place. He wanted to find out who murdered his fiancé himself. As he trained himself to become a better fighter and hunter, he found out Dara’s brother was shot and killed. Jung Min was so shocked; it was all too soon that her brother dies. He just graduated from college, and just arrived home to see Dara. Jung Min then got caught up in his step brother’s mess. Wondering why Seung Hyun is making deals with the gang SHIRI for and why is Ji Yong locked up for something he didn’t do. As Jung Min takes Dara in hiding after Cheondung’s burial, he then starts uncovering things as soon as he finds out who’s in SHIRI and why IRIS blames Junsu. How will Jung Min react to this? And will this man find out who kill his fiancé?

Kim Kyu Jong: A man who works for himself. A 23 year old guy who is working under SHIRI secretly, since he wants to kill the boss for killing his father. Kyu Jong was assigned to kill a person when he first joined SHIRI. Kyu Jong would do anything just to hopefully kill that SHIRI boss. So Kyu Jong just randomly picks a person and shoots him/her. During that time, another gunshot was heard, so he just left the place and goes back to SHIRI. The boss then gives him trusts and noble. Then one day a mysterious man comes to SHIRI for help, since the man hears that SHIRI wants to eliminate IRIS. IRIS is a big rivalry of SHIRI. The boss makes the deal with the man, but Kyu Jong refuses. But if he’s going to have the boss believe him, he let the mysterious guy make the deal. Kyu Jong then tries to befriend the new guy to get information of why he wants to make a deal with SHIRI to eliminate IRIS’ people. Kyu Jong then finds out why and was impressed at how a person is willing to do anything for a friend. But not for long did their friendship last, Kyu Jong regretted doing one thing in the past when he meets the guy’s friends. What is it that Kyu Jong fears? Also, do you think Kyu Jong’s plan will be a success?

Park Sang Hyun aka Cheondung/Thunder: A young 20 year old guy who just recently graduated from college in the Philippines. He returns home to his sister Sandara Park and was excited to see all the old buds who hung out with his sister. As he cooks lunch for everyone and Dara was about to shower, a young man a little bit older than him came in and shot Cheondung before Cheondung can even tell him to not shoot. Cheondung died on the spot and his last breath was, “Why?”

Ok Seung Hee: The young lady who was to wed Park Jung Min until she was murdered while walking to be in her fiancée’s arm. Died at the age of 22, and her case was closed as the cops couldn’t go any further about who killed her, since there were no witness in seeing any people or person with a gun or looking suspicious.

Ok Taecyeon: A young 21 year old detective who's trying to figure out the murderer of his sister. Even though the case is closed, to him, the case is still open. Although there are no evidence, he can find evidence for himself to find out who kill his sister. Ever since his sister Seung Hee's death, Taecyeon became totally different. Of course, loosing both parents at the age of 17, his sister took care of him only. Now loosing his sister too, Taecyeon became a cold person. He lost contact with his Seung Hee's fiancée; Park Jung Min. He was not close ot anyone except for his detective buddy Jang Woo Young. As Taecyeon went undercover for a case about drug dealing, he saw Jung Min's stepbrother, Choi Seung Hyun with the gang group SHIRI. Taecyeon was shocked by this. As he followed Seung Hyun slowly, it then led him to something unexpectedly and surprisingly. Ji Yong was in jail and he didn't even know why Ji Yong was locked up. He lost all contacts and now that he follows Seung Hyun, everything became a total blur. Will he find out about his sister's murderer? Will he become friends again with Jung Min? What does he think of Seung Hyun seeing Seung Hyun with SHIRI?

Nine guys, one guy uncovering the truth, two guys fighting for the spot, one guy who desperately needs the money, one guy in prison, one guy undercover, one widowed guy, one guy who's a detective, and one dead guy, and one girl who wants to know why her brother died, two unexpected murder, what will happen?

How will all these people deal with one thing and expect to be happy the next when there’s a saying, ‘What goes around comes around’?