A dead body is discovered at the Cape by a local volunteer coastguard Watchkeeper who decides in a spirit of Cornish self-reliance to pursue his own investigation of the affair, which is baffling the local police.

In the guise of holidaymakers, he and his slightly sceptical wife follow the clues to the shores of Lake Geneva in Switzerland where the pieces of the jigsaw begin to fall into place.

Constantly misled through their innocent proximity to the crime scene they are under hot pursuit. With the Cornish police now closing in on the investigation, can the couple escape before the conspiracy can take effect?