Three children, inspired by stories of a nearby shipwreck, spend their seaside holiday searching for a hidden treasure.

Two youngsters vacationing at the Black Sea sneak onto a mysterious ship and spy the peculiar activities of a treasure-seeking crew. They are discovered and imprisoned as the ship heads for an uncharted island. Their parents put together an expedition and after numerous adventures the treasure hunters are apprehended and the mystery of a secret cove is solved.—Polish Cinema Database <http://info.fuw.edu.pl/Filmy/>