Jang Do-yeong is a fiery homicide detective who prefers to fight first rather than talk, while O Jin-u is a dispassionate and perfect elite prosecutor. They were investigating separate cases, but realizing the cases are related, they form a team. Expanding the investigation, they realize the case is a huge conspiracy—that a gangster’s murder and secret strife are mingled, and Yu Gang-jin, the president of the Guryong Group and aspiring political figure, is also involved. Getting down to the case, Yu Gang-jin’s evil hand extends to Jang Do-yeong’s family, and outside coercion forces O Jin-u to stop the investigation. The two men are in danger and their wild instinct gradually awakes. They throw themselves into the bloody battle and the deadly war with the gangster boss begins…