In 1788, exactly one hundred years before Jack the Ripper terrorizes the people of London, a sexual miscreant known as the London Monster roams the streets in search of his next victim...

Thomas Hayes, having lost his mother in a vicious street assault, becomes an underground pugilist on a mission to rid the streets of violent criminals. But his vigilante actions lead to him being mistaken for the most terrifying criminal of all.

Assistance arrives in the form of Sophie Carlisle, a young journalist with dreams of covering a big story, though she is forced to masquerade as a man to do it. Trapped in an engagement to a man she doesn't love, Sophie yearns to break free to tell stories that matter about London's darker side—gaming, prostitution, violence—and realizes Tom could be the one to help. Together, they come up with a plan.

Straddling the line between his need for vengeance and the need to hide his true identity as a politician's son becomes increasingly difficult as Tom is pressured to win more fights. The more he wins, the more notoriety he receives, and the greater the chance his identity may be exposed—a revelation that could jeopardize his father's political aspirations and destroy his family's reputation.

Sophie is also in danger as hysteria spreads and the attacks increase in severity and frequency. No one knows who to trust, and no one is safe—Tom included, yet he refuses to end the hunt.

Little does he realize, the monster is also hunting him.