Nightshade (Hugh Corbett Series #16)

An unscrupulous manor lord has reneged on his promise to hand over a priceless ornate cross stolen from the Templars during the Crusades. Furthermore, he has massacred as heretics fourteen members of a religious order. The King sends Hugh Corbett, devoted emissary of King Edward I to Mistleham in his stead...

"Another fine historical mystery steeped in medieval atmosphere." - Kirkus Reviews