“Beautiful and important.”—New York Times bestselling author Julia Quinn

When a Victorian apothecary hires a stoic private investigator to protect her business, they learn there’s only one way to treat true love—with a happily ever after.

When Lucinda Peterson’s recently perfected formula for a salve to treat croup goes missing, she’s certain it’s only the latest in a line of misfortunes at the hands of a rival apothecary. Outraged and fearing financial ruin, Lucy turns to private investigator Jonathan Thorne for help. She just didn’t expect her champion to be so . . . grumpy?

A single father and an agent at Tierney & Co., Thorne accepts missions for a wide variety of employers—from the British government to wronged wives. None have intrigued him so much as the spirited Miss Peterson. As the two work side by side to unmask her scientific saboteur, Lucy slips ever so sweetly under Thorne’s battered armor, tempting him to abandon old promises.

With no shortage of suspects—from a hostile political group to an erstwhile suitor—Thorne’s investigation becomes a threat to all that Lucy holds dear. As the truth unravels around them the cure to their problems is clear: they must face the future together.