The murder of a female GP in a rural playground in front of numerous witnesses draws a group of detectives into an ever-darkening mystery that takes them across Europe, aided by mysterious notes sent by the "Ghost Detective".

• Indira Varma
• Robert Glenister
• Neil Stuke
• Christiane Paul
• Lesley Sharp
• Anjli Mohindra
• Dino Fetscher
• Michael Maloney