People of the Sea

What was the cargo of the small plane that divers had found among the old Greek ruin? Why had it spread death all across Europe from Russia to a small Greek Island?

Something was watching them as they swam around the temple. The divers saw flashes of light that came out of the gloom, then out of sight. At first they thought they were dolphins. What where these strange creatures that kept just out of sight? Why was the white yacht always in the area where the divers were? What were they looking for? Was the Agent from Interpol, really who he said he was?