In 1999, a recording tape containing a mysterious serial murder and an eerie sound is discovered in a rural town.
In 1987, terrorist Jo Gyeong Ho released sarin gas at a train station, killing passengers before turning himself in. His daughter, Jo Jae Yeong, was sent to live with his younger sister, Jo Jeong Hyeon.
A decade later, Detective Choi Hyeong investigates a murder case he suspects is linked to the past attack. When Jeong Hyeon's niece goes missing, she joins Choi Hyeong to uncover the truth and save her.
(Source: MyDramaList)
