The exciting new Richard Mariner marine adventure - Far into the East China Sea, Richard and Robin Mariner are testing the Neptune, their companys latest acquisition, an unmanned sub. A distress call comes in from a submarine whose mission is to recover the lost gold of Kublai Khan. It has become trapped on the seabed and the crew is running out of air. But as the Mariners guide Neptune to the rescue, a darker story becomes plain. Was the submarines voyage a cover for a more sinister mission?
