Natsuko Yotsuya (Ema Sakura) is a teenager and she is also known as Bon. She lives in a town and has a friend, Miyu-chan, who lives with her boyfriend in Tokyo.
Sawa Yamagishi (Sakura Ando) worked as a nursing-care helper. The family for an old man asked Sawa to sleep with him, which led her to eventually lose her job and house.
Black Coal, Thin Ice
An ex-cop and his ex-partner decide to follow up on investigation of a series of murders that ended their careers and shamed them, when identical murders begin again.