Pietro Gerber is not a psychologist like the others. His specialty is hypnosis, and his patients have one thing in common: they are children. Often traumatized, marked by dramatic events, or in possession of important information buried in their fragile memories, these children are essential to police and magistrates for ongoing investigations. Pietro is the best in all of Florence, known as ""the child sleeper.""

But when he receives a phone call from the other side of the world—from an Australian colleague recommending a patient—Pietro reacts with skepticism and distrust. Because Hanna Hall is an adult.

Hanna is haunted by a vivid memory, which may not even be real: a murder. And to find out whether that fragment of memory is true or just an illusion, she desperately needs Pietro Gerber.

Hanna is an adult now, but that memory dates back to her childhood. And Pietro must help her awaken the child still within her. A little girl with many names, always kept away from strangers, who lived happily with her family in a magical place: the “house of voices.