The passage describes the discovery of a sunken galleon ship from the 17th century off the coast of an unnamed northern bay. It had gone down with treasures from its voyages, but what and how much was uncertain. The Duchess of Dulverton believed the ship contained a valuable sunken treasure and learned of an invention that could precisely locate and recover objects from the seabed using electric suction dredging. Having a connection to the lineage of Medina Sidonia, she acquired the invention and apparatus to try to find the galleon's treasure privately, as previous companies had failed after centuries of attempts.