The consuming passion between Pedro I of Portugal and Ines de Castro is brutally interrupted when Ines is executed, as a consequence of political intrigue and in the name of the kingdom's interests. Pedro, cruelly hurt, pursues the single-minded purpose of avenging his lost love. He captures and kills the executioners, and compels the nobility to acknowledge Ines as his lawful wife and Queen of Portugal.

The Meldrews go on holiday to Portugal with Mrs Warboys, who is hoping for romance with her penpal Alfonso. Photographer Martin Trout follows them there, believing they have a roll of film that belongs to him.