Kim Hyun Joong is the leader of the biggest mafia ever. His four sisters formed they're own little gang and they all live together. They harbor all on the run gangs and mafias. Five undercover agents enter the house posing as a gang known as big bang. But when they're leader Gd begins to fall for one Hyun Joong's sisters, he begins to find complications with completing his job. Will he be able to keep it from her or get found out and killed?

CL and GD have loved each other since they first meet. But could never tell each other and so CL moved on. Jay park had asked her out and thinking GD didn't have feelings for her she said yes. But what CL doesn't know is Jay Park is cheating on her. GD found out and even told her but that didn't go to well. Will Gd ever get Cl to see Jay Park for how he truly is or will he just have to move on?