Hetty is called in to investigate when one by one, the contestants in the Blainthorp Muiscal Festival lose their voices. The sponsor of the festival, Oliver Hardiman wants the mystery solved but Hetty only has five days.She finds herself caught up in a battle between rival pharmacists who may be using their skills to harm the finalists.

• David Cook
• John Bowen

• George Costigan
• Anne Reid
• Dominic Monaghan