Pietro Gerber is a psychologist, but not like the others. His specialty is hypnosis, and all his patients are children to whom something has happened: they have suffered trauma, witnessed dramatic events, or have important information stored in their fragile memories that can help the police or child protection authorities in an investigation. But from the other side of the world, from Australia, a colleague calls the psychologist and asks to see a patient.

Pietro is perplexed why he should contact him, since Hannah Hall is an adult. It turns out that the young woman is haunted by the memory of a certain murder, allegedly committed by her in childhood. And to understand whether this is true or an illusion, she needs the best psychologist in Florence - Pietro Gerber.