The story:
Relocating as a UN nurse to the Caribbean with Dr. Kirk and his colleagues after the harrowing events in Bengali (see D083 The Epidemic and D085 The Mysterious Ambassador), Diana finds time for recreation in the form of scuba-diving in the nearby coral reefs, partly to get away from the intrusive advances from a Mr. Raye.

Meanwhile, the Phantom has decided to take a rare vacation in the Caribbean to be with Diana on her long assignment, but is immediately thrust into an investigation concerning Diana's death in a diving accident...