This film goes in search of an ancient warrior civilisation built on gold, but until now lost to history. Travelling to the plains of central Europe, we have exclusive access to sites so rich, the locations and digs are state secrets.  We make incredible discoveries thousands of years old, including a solid gold mask belonging to a mighty king. Part of the biggest hoard of ancient European gold ever discovered, they are links to the amazing people of Thrace, a vanished civilisation which existed before the Romans and even the Greeks.