A Feast of Poisons — C.L. Grace

The village of Walmer is a small, claustrophobic place where everyone knows everyone and everyone's business. Everyone knows the blacksmith, Elias, liked to drink and liked the ladies. Everyone knows his wife, Isabella, had been spotted many a time entering the woods with men other than her husband. And everyone knows the couple fought, sometimes violently.
But could they have independently, and on the same day - the festive eve of Michaelmas - murdered each other with two entirely different poisons? The village's medicine woman, Mother Croul, doesn't think so. And neither does Kathryn Swinbrooke, Physician of Canterbury, who is in town with her new husband, Colum Murtagh.
Kathryn and Colum are visiting on state business: Lord Henry Beauchamp is to receive the shadowy emissaries of Louis XI of France, on behalf of his own master, Edward of York, only recently triumphant over Lancastrian forces in the bloody, fratricidal War of the Roses. The Frenchmen claim to have the ultimate bargaining chip - but do they?
It is a tense time for the kingdom; everything hinges on the meeting between Lord Henry and the French agents. Now murder stalks the land, and only Kathryn Swinbrooke can cut through the web of murder and deceit that seems to arrive with the Spider King's minions.