The Good Detective follows the lives of detectives in Incheon, South Korea, as they navigate the complexities of the justice system. The story centers on Kang Do-chang, a veteran detective with 18 years of experience who relies on his intuition and personal connections, and Oh Ji-hyeok, an elite detective who prefers to rely on evidence and logical deduction. Despite their clashing methods, the two form an unlikely partnership to uncover hidden truths behind cold cases. As they delve deeper into their investigations, they find themselves entangled in a web of corruption involving powerful figures, media manipulation, and past judicial mistakes. The series explores the moral dilemmas faced by those in law enforcement, highlighting the struggle between upholding the law and seeking true justice in a system often influenced by wealth and status.