Twenty-one years ago, Dr Richard Carter and his wife Pamela were killed in what has become the most infamous double murder of the modern age.

Their ten year-old daughter – nicknamed the Angel of Death – spent eight years in a children’s secure unit and is living quietly under an assumed name with a family of her own.

Now, on the anniversary of the trial, a documentary team has tracked down her older sister, compelling her to break two decades of silence.

Her explosive interview sparks national headlines and journalist Brinley Booth, a childhood friend of the Carter sisters, is tasked with covering the news story.

For the first time, the three women are forced to confront what really happened that night – with devastating consequences for them all.