The untold story of the killer nurse.

Lucy Letby seemed like a totally ordinary young woman: fun-loving and sociable. Those who knew who say she had a happy childhood with devoted parents, and after university she landed her dream job as a nurse looking after sick babies. She even became a poster girl for the hospital where she worked.

And yet today, Lucy Letby is officially the most prolific child killer of the modern era. Following one of the longest murder trials in British legal history, she's been convicted of murdering seven babies, and attempting to murder seven others. She is only the fourth British woman ever to receive a whole life prison sentence. Still only in her thirties, Letby will die in prison. But although her journey from obscurity to infamy has made headlines across the world, very little is known about her. Meanwhile, her convictions have attracted unprecedented controversy with a growing number of critics arguing that she may in fact be innocent.

So who is the real Lucy Letby? What was she like according to those who knew her best? What happened at the hospital where she worked? And what convinced senior medics and the police that she was killing babies?

Despite trying and failing to appeal her convictions, Letby has maintained her innocence and no one ever saw her harming a baby - which is one reason why this case has become so controversial. Could Lucy Letby be the victim of a miscarriage of justice, as her supporters believe, or is she the cruel, calculating killer that the jury found her to be?

Drawing on extensive interviews with people who knew and worked with her, as well as unrivalled access to sources and documents, this book traces the story of Lucy Letby from primary school to prison, and grapples with the truth about one of the most high-profile murder cases in living memory.