An Edinburgh professor and assorted colleagues follow an explorer’s trail down an extinct Icelandic volcano to the earth’s center.

Sam Whiskey is an all-round talent, but when the attractive widow Laura offers him a job, he hesitates: he shall salvage gold bars, which Laura’s dead husband stole recently, from a sunken ship and secretly bring them back to the mint before they are missed. But how shall he manage to get several hundred pounds of gold into the mint without anyone noticing?