The river knows - Amanda Quick

The first kiss occurred in a dimly-lit hallway on the upper floor of Elwin Hastings's grand house. Louisa never saw it coming ...Of course, Anthony Stalbridge couldn't possibly have had romantic intentions. The kiss was an act of desperation, meant to distract the armed guard about to catch the pair in a place they did not belong. After all, Louisa Bryce is no man's idea of an alluring female in her dull maroon gown and gold-rimmed spectacles. The only thing the two interlopers have in common is a passionate interest in the private affairs of Mr. Hastings - a prominent member of Victorian Society whom they both suspect of hiding terrible secrets. Each has a reason for the quest. Anthony's fiancee was said to have thrown herself into the Thames - but Anthony has his own suspicions. Louisa - whose own identity is shrouded in layers of mystery - is convinced Hastings has a connection to a notorious brothel. But bringing Hastings to justice will be more perilous than either anticipates - and their hasty partnership will be more heated than either expects.