It's a baking hot British summer, and the sleepy town of Market Foxleigh is staging a crime writing festival... with the three Dahlias as guests of honour. After all, not only have Rosalind King, Caro Hooper and Posy Starling each played fictional detective Dahlia Lively on screen, but they're also making a name for themselves solving real-life murders too.

The Dahlias are anticipating a weekend of cream teas, awards dinners and warm white wine... but before long they're sleuthing together once again - this time helping a true crime podcast investigate a local cold case with a personal connection for one of the Dahlias. It's been five years since Dahlia Lively fan Scott Baker was arrested for a murder that had eerie echoes of one of Dahlia's fictional cases.

It seemed like an open and shut case at the time, but the podcast team are convinced that the police got the wrong man. Can the three Dahlias help prove them right - and find the real killer?