At dawn one morning in 1933, an amateur dowsing team digging the banks of the Thames for precious metals unearths the body of a young woman with a priceless gold coin in her mouth. The case falls on Joe Sandilands' turf, but he's been given another assignment - London is hosting a historic global conference to try to solve the Depression and political tensions are running high. His job is to keep an eye on American senator Cornelius Kingstone, right-hand man to President Roosevelt. But when the Senator is linked to the body, Joe realises his assignment is bigger than he thought.