Moo Jin-hyuk (Jang Hyuk) is a "mad dog" detective who becomes guilt-ridden after his wife was murdered while he was at work. Kang Kwon-joo (Lee Ha-na) is a tough policewoman who is gifted with perfect psycho-acoustics skills. She was working at the call center when a brutal murder case takes place and in the process of investigating her father was killed. Three years later, Jin-hyuk and Kwon-joo team up as the "Golden Time team" and solve cases together, chasing after the serial killer who took their loved ones.