1951.

Inspector Alun Ryga surveys the wreckage of the elegant Harley Street drawing room. It's the home of retired dermatologist Sir Bernard Crompton, who's currently sailing his new yacht down the British coast from Scotland - or so he was . . .

Sir Bernard is found dead on board his boat off the coast of Cornwall. The doctor declares he died of natural causes. But why was he wearing a dinner suit with five rocks in his pocket?

Ryga heads to Cornwall to investigate, but the case takes a deadly turn when another body is found in a nearby cove with a gunshot wound to the face. The victim is also wearing a dinner suit with rocks in his pocket . . .