In episode one, we hear the shocking testimony of Kathy, former nightclub queen and prison officer, who entered into a loving relationship with Stephen Griffiths, later to be known as the "Crossbow Cannibal".

She describes how their relationship blossomed after they first met on a night out in Bradford, and how Griffiths increasingly controlled and coerced her, spiking her tea, stealing her dogs, locking her up and beating her. As the story of Kathy's troubled relationship with Griffiths unfolds, criminologists share details of the horrific killings of local sex workers who disappear one by one in the area where Kathy lives. Kathy reveals how Griffiths took her to visit the scene of a mysterious and horrific murder that occurred close to his flat, and how his behaviour became increasingly disturbed as he descends into a lifestyle of hard drugs and leaves chilling and threatening messages on Kathy's phone - messages that feature in the programme.

Kathy recalls how her nightmare relationship with Griffiths finally came to a sickening end when she receives a visit from the police who revealed the awful truth about her partner: Griffiths was responsible for three horrific murders, including a local woman he shot through the head with a crossbow which was caught on security camera.

Kathy reveals how she reacted as she learned about the gruesome details of the murders including the mutilation and dismemberment Griffiths inflicted upon his victims, and his claims that he ate parts of their bodies. She also details how she struggled to process that the man she'd been with had committed such heinous crimes.

Finally, Kathy describes what it was like coming face to face with Griffiths as he was sentenced to life imprisonment, how she has come to terms with the horrors she endured for so many years, and how she paid her respects to the victims with a touching personal act.