When Eliza's father dies, he leaves her penniless in a time where marriage is the only option for financial security. But the headstrong Eliza has an ace up her bonnet - her father's business, a detective agency. But it's Victorian London and, to operate in this man's world, she needs a partner.

Step forward consummate rogue Detective Inspector William Wellington of Scotland Yard, aka "The Duke".

Eliza and Duke strike up a fiery relationship as they team up to solve puzzling crimes in the murkiest depths of 1880s London.