The River Knows by Amanda Quick

From New York Times bestselling author Amanda Quick comes a delightful romp filled with breathtaking suspense, dazzling wit, and steamy Victorian passion...
 
The first kiss occurred in a dimly-lit hallway on the upper floor of Elwin Hastings’s grand house. Louisa Bryce never saw it coming. Of course, handsome, wealthy Anthony Stalbridge couldn’t possibly have had romantic intentions. The kiss was merely meant to distract the armed guard about to catch the two unlikely sleuths. After all, the only thing these two interlopers have in common is a passionate interest in uncovering the dastardly secrets of Mr. Hastings—a prominent member of Society whom they suspect of murder.  
 
Brought together by their desire for the truth, Anthony and Louisa finally discover the incriminating evidence they’re looking for. But bringing Hastings to justice will be more perilous than they anticipate, especially since their thrilling attraction to danger—and, it turns out, to each other—might very well get in the way...