For the estranged ex-lovers, bringing the notorious assassins to justice proves as tumultuous as quelling pent-up desires. Fighting peril and passion at every turn of a dangerous journey from Edinburgh to London, they are pursued by an anarchist group hell-bent on destroying her father's mysterious entry into the London Industrial Exposition.
When an astonishing discovery about the couple's failed engagement surfaces, the sleuthing duo realize they can trust no one. Rafe confesses new details about his infidelity and Fanny risks all to avenge her father's murder. But will Rafe and Fanny triumph over the pain of their past?