"The best detective in South Korea, the top graduate of the police academy, a flawless police officer with outstanding achievements in every field!" This is about Kang Da-yeon, a detective from South Korea's violent crimes unit. She has been assigned a new task, aptly named 'Gang Investigation'! The ultimate goal is to uncover clues about the illegal financial merger of two organizations and apprehend key figures within the organization. Among those tasks, she must build a friendship with Eun Eun-han, the only daughter of the boss Eun Do-sik, who leads the nationwide organized crime group 'Bisanpa'! But……. "How old are you, unnie? You're really tall! Did you work out? I'm about to bounce out of here... If I do, I'll be caught by you first, right? Since you're next to me?" Damn it, what am I supposed to do with this little troublemaker! An action-packed love story between Kang Da-yeon, who works tirelessly for the case, and the innocent troublemaker Eun Eun-han!