Jack Scott and Sian Laidlaw are forced to remain in Gibraltar with Jack's mother when she breaks her ankle - Eleanor believes she was pushed. When a chance meeting with a young photographer, Pru Wise, leads them into the path of trouble and up against a ruthless diamond robber it becomes clear that there are some dangerous forces at work. Returning to the UK, Jack and Sian are shocked when Pru's dead body is discovered in the boot of a car registered to Sian. When threatened they return to Gibraltar, to try and seek out and identify the diamond thief and end the nightmare. But first they must unravel a web of intrigue, face a violent climax in the house of an ex-diplomat, and face a fight to the death on the rocks of Gibraltar's most southerly shore.