London, 1887. As the city prepares to celebrate Queen Victoria's Golden Jubilee, Veronica Speedwell is marking a milestone of her own. After burying her spinster aunt, orphaned Veronica is free to resume her world travels in pursuit of scientific inquiry—and the occasional romantic dalliance. As familiar with hunting butterflies as with fending off admirers, Veronica wields her butterfly net and a sharpened hatpin with equal aplomb, and with her last connection to England gone, she intends to embark upon the journey of a lifetime.

But fate has other plans, as Veronica discovers when she thwarts her own abduction with the help of an enigmatic German baron who has ties to her mysterious past. Promising to reveal in time what he knows of the plot against her, the baron offers her temporary sanctuary in the care of his friend Stoker, a reclusive natural historian as intriguing as he is bad-tempered. But before the baron can deliver on his tantalizing vow to reveal the secrets he has concealed for decades, he is found murdered. Suddenly Veronica and Stoker are forced to go on the run from an elusive assailant as wary partners in search of the villainous truth.