A group of men calling themselves 'The Pirates of Capri", headed by Captain Sirroco, who is really Count Amalfi, are trying to restore freedom to the people of Naples in 1799. The Queen is advised of the pirate's assault of a member of her court and she seeks to escape to Palermo. But, she is advised it would be good politics for her to attend a ball Amalfi is giving for his fiancée, Mercedes, who is unaware of the dual role Amalfi is playing.