On his death bed, Lord Pembroke took great care to try to ensure the future of his beautiful, unconventional niece, Lady Jane. Her debutante ball featured the most eligible bachelors of London society. But when the night of the dance arrives, things do not go as planned.

To escape the superficial drama of the party, Jane seeks refuge in the garden of Rosewood Hall, where she discovers a gravely injured girl. With her last breath, the child beseeches Jane to find another girl, Mary, and to save her from the same fate she has suffered. Lady Jane vows to fulfill this final wish, a promise that will entangle her in a dangerous intrigue and take her from the safety of home to the hard streets of London. With the faded inscription in a tattered novel as her only physical clue, Jane sets out to investigate the region's orphanages and infiltrate London's most elegant homes. Can she save young Mary from a swiftly approaching doom?