Moo Jin Hyuk (Jang Hyuk) is an outstanding detective, but when his wife (Cha Soo Yeon) became the latest victim of a serial killer, his world falls apart. Wracked by guilt, he turns to alcohol and behaves peculiarly while everyone around him understandingly grants him leeway. Meanwhile, Kang Kwon Joo (Lee Ha Na) graduated top of her class at the police academy and was working as a 112 call centre operator when she took the emergency call from Jin Hyuk’s wife. Gifted with extraordinary hearing abilities, she inadvertently ends up overhearing the serial killer murdering her own father, a police sergeant. Devastated, Kwon Joo goes to the United States to further her studies in voice profiling and returns to Korea three years later to head up a 112 call centre. She establishes a special Golden Time Task Force to become the first responders in time-critical 112 emergency calls. Coerced onto the Golden Time Task Force are Jin Hyuk, his partner Shim Dae Shik (Baek Sung Hyun), master computer hacker Oh Hyun Ho (Yesung) and multilinguist Park Eun Soo (Son Eun Seo). Bound by a common enemy, Jin Hyuk and Kwon Joo track the serial killer that took their loved ones away. Together with the other members of the Task Force, they dedicate their lives to fighting crime using the limited information they have from the urgent calls they receive. The crime victims are often held captive or being chased by their assailants. Can the Golden Time team get to them in time? Can Jin Hyuk and Kwon Joo hunt the same serial killer responsible for the loss of their loved ones years ago?