"Investigating how a severed hand ends up on the third green of a Cumbrian golf course is not how Detective Inspector Avison Fluke has planned to spend his Saturday. So when a secret protection unit from London swoops in quoting national security, he's secretly pleased. But trouble is never far away. A young woman arrives at his lakeside cabin with a cryptic message: a code known to only a handful of people and it forces Fluke back into the investigation...