3rd September 1939. A Secret Service agent breaks into Maisie Dobbs' flat to await her return. Dr Francesca Thomas has an urgent assignment for Maisie: to find the killer of a man who escaped occupied Belgium as a boy, during the Great War some twenty-three years earlier.
In a London shadowed by barrage balloons, bomb shelters and the threat of invasion, within days another former Belgian refugee is found murdered. And as Maisie delves deeper into the killings of the dispossessed from the 'last war', an evacuee from London appears in Maisie's life, bringing the current crisis close to home.
As Maisie's search for the killer escalates, the country braces for what is to come. Britain is approaching its gravest hour – and Maisie could be nearing a crossroads of her own.