The Perfect Poison by Amanda Quick
Victorian botanist Lucinda Bromley has a rare talent: the ability to detect almost any type of poison. She also tends many rare plants, including a species of fern that was stolen from her conservatory just last month--and which turns up in a poison that was used in a nobleman's murder.
To keep her name out of the investigation and to find the killer, Lucinda hires a fellow Arcane Society member. The founder of a psychical investigation agency, Caleb Jones is very good at protecting the Society's secrets--and frighteningly good at getting the truth.
As a nearly overwhelming desire blooms between Caleb and Lucinda, they are drawn into the dark heart of a deadly conspiracy--and into a legacy of madness that could plunge Caleb into the depths of his own tortured soul...