Music critic Hugo Belcher, in 21st century London, is a charming rogue who, forever short of money, plans to marry a wealthy young heiress. Meanwhile, Sandra Grisewood, a bright working class girl, moves to London where she hopes one day to realise her dream of becoming an opera singer. Born in 18th century Prague, music teacher Antonin Vasylicek, another rogue and charmer, flees to England to evade his creditors and escape a scandal. Their separate lives are, however, inextricably linked in various ways...not least the discovery in Bloomsbury of the score of an opera, based on Carlo Goldoni's comic play 'The Servant of Two Masters', which a renowned musicologist believes could be a lost Mozart opera.