The First Contact Gold Swindle is the retronym for a period of contact between administrations of the governments of major countries of Earth A and some unidentified clan of Traveller (Rename)s.

The Clan (Rename)

Traveller Clan (Rename) are, like almost all of their species, nomadic. But while most clans migrate between existing centers of intergalactic civilization, some prefer to navigate its frontiers, taking advantage of the naivete of isolated species. 

The Swindle

The Clan had initiated contact with various contacts on Earth, of high enough clearance to access gold reserves but low enough to not know the real truth about existing human contact with other races. They included administrators from The US, The PRC, Germany, Italy, France, Russian Government, Switzerland, Japan, India, The Netherlands.

<TODO: These links are very non-uniform - some refer to locations, others to Organizations, and maybe more.>

The story they told Earthlings was that they had received contact from SETI or equivalents, but we need to stay quiet or The Predators will hear us. The Predators are an entirely fictional race that exterminate everything they come in contact with. The Clan said they themselves were refugees from a civilization that had been destroyed by the Predators, but they knew how to build a superweapon that would extinguish them. The only problem was, they needed a bunch of gold and obviously couldn't grab it on the way out. So if we would be so kind and generous as to give them all of Earth's gold, they could kill the mean Predators for us and they'll give it all back, promise.

Once the transaction was complete, the Clan disappeared without a trace with a good chunk of the gold on earth. Fort Knox, along with most of the other major gold repositories on earth, has been pretty much empty since the Nixon administration. The countries that fell for the scam have been in on an international coverup since then to pretend that nothing is awry.