South-east London, 1925. Talented, ambitious designer-dressmaker Rose Burnham knows well both the strains of her profession and the secrets it can yield. Newly established in her own business, she and her sisters are privy to the hushed conversations that unspool behind the fitting room's closed doors. So when a major client finds herself the victim of a deception, it is Rose she tells. Driven by the shortage of men following the Great War, Miss Holmes had engaged the services of a matrimonial agency, only to be cheated out of her inheritance by a fake suitor. Rose is determined to bring the swindler to justice. To begin with, playing the detective is a grand adventure, but as pressures mount and an old friend receives a troubling string of poison-pen letters, Rose discovers there is more to investigating - and these investigations - than she'd bargained for.