Hervé is a tough sea captain in command of the "Duchesse Anne", a rum-trading ship. But the sea dog hides a tender heart and he allows Marie-Douce, a poor slum girl who dreams of seeing the wide world,on board. To have her accepted by the crew, he passes her off as his niece. A seasoned master like him, wise enough to ban alcohol use on his ship, should have known better : a beautiful girl on the deck cannot but unleash the savage instincts of all those men without women...