A thief with golden eyes. The spy who loves her. A mad scientist who will break hearts to expose her secrets.

Shunned for her odd eyes and an unnerving habit of slipping into shadows, Lady Colleen Stewart refuses to be caged—should she decide to marry, it'll be for love and to a man of her choice. After all, she'd rather be racing over rooftops than waltzing across ballroom floors. So when the only man to ever tempt her heart invites her on a covert mission, she leaps into danger.

Nicholas Torrington, Queen's agent, is running out of time. While work has him chasing his tail, his sister grows increasingly ill, and Colleen, the woman he would make his bride, has acquired another, determined suitor. To coax his favorite thief back into his arms, he'll break every rule and lead her through the underbelly of London on a hunt for a mad scientist and a cure for his sister.

But the discovery of a burned-out laboratory provides more questions than answers, and they find themselves caught in a deadly game where they have become the prey. Surviving the ambitions of their pursuers will bring everything into sharp focus as they risk their very lives.