Abandoned at the gates of a London park one winter's night in 1850, baby Lily Mortimer is saved by a young police constable and taken to the London Foundling Hospital. Lily is fostered by an affectionate farming family in rural Suffolk, enjoying a brief childhood idyll before she is returned to the Hospital, where she is punished for her rebellious spirit. Released into the harsh world of Victorian London, Lily becomes a favoured employee at Belle Prettywood's Wig Emporium, but all the while she is hiding a dreadful secret. Across the years, policeman Sam Trench keeps watch over the young woman he once saved. When Sam meets Lily again, there is an instant attraction between them and Lily is convinced that Sam holds the key to her happiness - but might he also be the one to uncover her crime and so condemn her to death?