A Portuguese family works out to make ends meet: Rosa as a restaurant cook and Antonio, her son, as a tour guide; his father helps him vaguely by pretending to be a ghost in a hunted mansion, but mostly boozing the family's earnings. Mercedes is a rich Argentinian girl, who will be the sole heiress when her father dies, is one of the many tourists flocking into Antonio's sightseeing tour of Lisbon. Antonio makes an escapade alone with Mercedes to Sintra, and the romantic setting aiding, they fall in love. However, Mercedes' father, living in Geneva, Switzerland, suspects that Antonio may be just a fortune hunter, and dispatches an undercover detective to Lisbon to find out. Claudia Bronner exposes Antonio's lack of professionalism as a tour guide - but falls in love with him. The worried father comes to Lisbon himself, and is prey to a mature Baroness Karaczyl, a woman who collects jewels offered by old gentleman who fall for her at the Palace Hotel. In the end, problems are solved, and many find «love in Portugal», as the French film title says.