A 30-year-old Charles II is rapturously welcomed back on the throne after years in exile. Needing funds he marries the wealthy Portuguese princess, Catherine of Braganza. But this is an unsuccessful match to his unattractive princess fails to provide him with an heir and the dowry never materializes. Although Charles always treats her with the utmost kindness, Catherine has to tolerate his many mistresses, notably the promiscuous beauty, Barbara Castelmaine.
The plot unfolds against a background of Plague, the Popish Plot and the Great Fire of London where underlying religious tensions promise to cause problems for the King. When his Catholic brother, James, looks likely to succeed him, the people rise up against Catholics. Even Queen Catherine is in danger when she is accused of plotting to kill her husband.