Plagued by rumors that she poisoned her fiancé, Lucinda Bromley manages to live on the fringes of polite society, tending her beloved plants — and occasionally consulting on a murder investigation. For the notorious botanist possesses a unique talent: she can detect almost any type of poison, especially ones that have their origins in the botanical kingdom. But the death of a lord has shaken Lucinda to her core. At the murder scene, she picks up traces of a poison containing a very rare species of fern. So rare, in fact, that only one specimen exists in all of England — and it was stolen from her conservatory just last month. To keep her name out of the investigation and to find the murderer, Lucinda hires a fellow Arcane Society member.

Caleb Jones runs a psychical investigation agency. A descendant of the founder of the Society, he is very good at protecting its secrets — and frighteningly good getting at the truth. Immediately, Lucinda senses both a raw power and undeniable intensity in the imposing man. But as a nearly overwhelming desire blooms between Caleb and Lucinda, they are drawn into the dark heart of a deadly conspiracy that can be traced to the early days of the Arcane Society — and to a legacy of madness that could plunge Caleb into the depths of his own tortured soul…