A former British naval officer now makes his living by smuggling goods around the Mediterranean. After being forced to dump his cargo when nearly caught by the authorities in Malta, he is eager to recoup his losses. When a former colleague appears and tells a wild story about smuggling diamonds out of south-west Africa, he sees his chance to make a lot of money. The diamonds are hidden in a shipwreck buried in the sand dunes of Namibia'sSkeleton Coast.
In recurring flashbacks, the captain relives his wartime experiences as the commander of a Royal Navy submarine, sent to South African waters to destroy an experimental U-Boat.
