Dulwich library is the scene of a murder, followed swiftly by another in Manchester, the victims linked by nothing other than their Australian nationality. Police dismiss the idea of a serial killer, but journalist Hannah Weybridge isn't convinced. She is drawn into an investigation in which more Australian men are killed as they try to trace their British families. Her research reveals past horrors and present sadness, and loss linked to children who went missing after the Second World War. Have those children returned now?

Once again Hannah finds herself embroiled in a deadly mystery, a mystery complicated by the murder of Harry Peters; brother of Lucy, one of the residents of Cardboard City she had become friendly with. It soon becomes clear Lucy is protecting secrets of her own - what is Lucy's link to the murders and can Hannah discover the truth before the killer strikes again?