A mechanical problem forces a Portuguese Navy Pilot to land on the Atlantic Ocean off the islets of Berlengas. Julião, an experienced sea-wolf, and his crew of fishermen, Pedro, Lacrau and Serrote, fish the pilot, and bring him safely ashore. The pilot is rescued at the manor house of the largest isle, where a beautiful girl lives alone. Rosa's humanitarian interest in helping the young man soon converts in a romantic fancy. When he returns to Lisbon, in the continent, she goes with him - and is engulfed in the lively customs of the city, with dress-up balls, dancing, night-clubs and ladies of the night, gambling, and drinking.