Luxurious Madderly Castle hosts velvet tapestries, hidden doors, slinking servants... and a murdered houseguest, Baron Glenelg. Ordered by Queen Elizabeth to help chatelaine Eleanor Madderly complete a new book on botanical decoctions, Susanna soon realizes there is more to the royal request when she finds out the victim was face down upon an herbal - the very one she herself authored. And when one lady and then another perish in a brutal manner, Susanna must unmask the killer quickly, before she becomes the next to die...