London, February 1914. Eighteen year-old Grace Campbell arrives in London from Carlisle, her family's hopes pinned on her becoming a secretary.
The only job she can find is as a housemaid in the mansion that is Number 35, Park Lane, and soon she is entangling herself in an ever-thickening web of lies.
Upstairs, a jilted and humiliated Beatrice Masters is determined not to return to the New York of her childhood before she has salvaged her pride. She secretly joins Emmeline Pankhurst's militant suffragettes and is steadily drawn into the violence rocking the city.
But Grace and Beatrice's existences are not as parallel as they seem. Little do they realize that their hidden lives and emotions will soon be revolving around the same man - or that the coming war will change the boundaries of both their worlds forever.