* Mona Golabek: The protagonist of the story. She is a young Jewish girl who flees Vienna with her mother just before the outbreak of World War II.
* Lisa Golabek: Mona's mother, a talented concert pianist.
* The Golabek Family (unnamed in the book): Mona's extended family who she left behind in Vienna. They are all victims of the Holocaust.
* The Kestenberg Family: A Jewish family who takes Mona and her mother in when they arrive in London. They are kind and supportive and become like family to them.
* The "Children of Willesden Lane" (Collective): This is the group of young, orphaned, or displaced Jewish children who were brought to London for safety during the war. They were often placed with foster families or in institutions, They are represented in the story through Mona's experiences and her connections with them.
Other notable characters include:
* Mrs. Kestenberg: The matriarch of the Kestenberg family who provides Mona and her mother with a safe and loving home.
* Mr. Kestenberg: The patriarch of the Kestenberg family who helps Mona and her mother settle into their new life in London.
* Esther: A close friend of Mona's, who she meets at the "Children of Willesden Lane" organization.
* Sir Adrian Boult: A famous British conductor who gives Mona a chance to perform with the London Philharmonic Orchestra.
The novel centers around the relationships between these characters, the challenges they face, and their collective resilience in the face of adversity.