Felicity Mayson is a merchant’s daughter with a small dowry. She receives an unexpected invitation to Lady Blackston’s country home and is introduced to the wealthy Oliver Ratley, who asks for her hand in marriage. Felicity is unaware that Lady Blackston and Oliver are leading a group of revolutionaries with a plot to undermine the monarchy. Philip McDowell is a government agent who asks Felicity to help him uncover the rebels’ secrets by continuing to act like an innocent bride-to-be and help him to expose the traitors.