Ollie, John, and Arthur, once mudlarks turned boarding school students through Charles Dickens’s aid, go missing along with a treasure map. Charles and his fiancée Kate Hogarth arrive at the school to search for them but find a servant girl strangled, connected to the missing map. Dickens and Kate race against time, dodging dangers to find the boys and the map, fearing for their lives amidst hidden treasures and murder.