The Earl of Wrexford possesses a brilliant scientific mind, but boredom and pride lead him to reckless behavior. He does not suffer fools gladly. So when pompous, pious Reverend Josiah Holworthy publicly condemns him for debauchery, Wrexford unsheathes his rapier-sharp wit and strikes back. As their war of words escalates, London's most popular satirical cartoonist, A. J. Quill, skewers them both.

Celebration is in the air at Wrexford and Charlotte's country estate as they host the nuptials of their friends, Christopher Sheffield and Lady Cordelia Mansfield. The festivities are interrupted when the local authorities arrive with news that a murdered man has been discovered at the bridge over King's Crossing. Lady Cordelia is horrified when the victim is identified as Jasper Milton, her childhood friend and a brilliant engineer who is rumored to have discovered a revolutionary technological innovation in bridge design.

With her inquisitive mind, Charlotte Holmes has never felt comfortable with the demureness expected of the fairer sex in upper class society. But even she never thought that she would become a social pariah, an outcast fending for herself on the mean streets of London. When the city is struck by a trio of unexpected deaths and suspicion falls on her sister and her father, Charlotte is desperate to find the true culprits and clear the family name. She’ll have help from friends new and old—a kind-hearted widow, a police inspector, and a man who has long loved her.

Determined to find the men responsible for her disgraced father's murder, Lady Arianna Hadley disguises herself as a man and contrives to be hired as a chef in one of London's aristocratic households. But when the prince regent is poisoned by Arianna's special chocolate dessert, she finds her own quest has become intertwined with a far more deadly intrigue. The earl of Saybrook is asked by the government to investigate. When someone tries to kill them both, they become reluctant allies in the hunt to discover what evil is afoot.

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, the 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 she is fending off admirers, Veronica wields her butterfly net and a hatpin with equal aplomb, and with her last connection to England gone, she intends to embark upon the journey of a lifetime.