Few of the boys who read about the adventures of the famous Captain Nemo managed not in a dream, but in reality to “steer” a real submarine and get on it all the way to the Mediterranean Sea. Dima and his enterprising younger brother Alyosha succeeded. In addition, they managed to find a sunken ship with countless treasures in its holds. But, as it turned out, finding a ship in the depths of the sea and recovering gold bars from it is still half the battle. The most important thing is to escape the pursuit of the bandits who decided, at all costs, to take possession of the treasures...