Rosemary and Laura are called to Vincent House Health Spa to rejuvenate 'The Dell' a water cascade designed by a women named Fenella Gothe, who has since died.

Fearing they may not be able to get the water running again, they are surprised when Frances Caldecott, the owner of the site, requests a whole new plant arrangement to the one her late husband Edwin originally chose.

Rosemary is given a book entitled 'The Language of Flowers' written by Edwin before he died, but not published until recently. In the book, Edwin has documented how different flowers can symbolize a range of actions and emotions.

Laura and Rosemary are invited to dinner with Frances and her children Kate and Jeff. When Frances doesn't arrive, the party are shocked to find her strangled in her study...