A serial murder case broke out in Wangye Town in 2008. Kiryu Aoi lost her family, friends and love, and her father became a suspect and was arrested.Sixteen years later, detective Aoi returned to her hometown to investigate the truth and discovered that her classmate might be a suspect, while her partner Kei Kasaka was monitoring and suspecting Aoi.During the investigation, she revealed the truth about her classmates and Hui's past, as well as the connection between the two incidents.Then, a truth that had been hidden for 16 years came to light.