Mallory Bright is the only daughter of London's most ingenious locksmith and has apprenticed with her father since childhood. After scandal destroys her reputation, Mallory has returned to her father's home and lives almost as a recluse, ignoring the whispers of their neighbors. But Sir Francis Walsingham, Queen Elizabeth's spymaster and a frequent client of Mallory's father, sees potenial in Mallory and draws her into his world of danger and deception....