In January 2016, businesswoman Sadie Hartley was brutally stabbed to death in her own home. This film follows Lancashire Police as they investigate the case from the call-out to the murder scene to the trial of the two female suspects.

Charlie and Alison are in love and it's the real deal. Their time together is abruptly cut short, however, when one morning Charlie wakes to find the back door to their apartment is wide open, and Alison is nowhere to be found. Vanished from his life without a trace, a heartbroken Charlie eventually moves on. Years later, living with his beautiful new fiancee, and having all but forgotten Alison, Charlie receives a mysterious package. The horrifying discovery inside will bring Alison back into Charlie's life in a terrible new way.