The movie was old and about a family who were living in a coastal village (probably Italy). The traditional occupation of villagers was fishing. There were masters who owned boats and workers. Business cycle was working in warm seasons, and keep fishes in salt for cold seasons were the prices was high.
This family has three sons and at least one daughter. Although the family was poor like other worker families one of the sons was educated and started to thinking why we should not be master. He convinced family to loan from bank and buy a boat and after debt payback they have the house and boat and become master of their own.
Everything went good until a day which seems to be stormy. They was under pressure for loan and despite other workers warning they went fishing. They lost the boat and problem begun. They started by selling stored fish in wrong season under the price. They lost their house. The junior brother started working with a criminal and the daughter became a whore.
Moral: Incomplete knowledge is much more dangerous than complete lack of it.