A couple of divers open a beer on the coast of the Mediterranean Sea. They have a successful dive behind them - they found another proof of the achievements of a Czech officer on board an Austrian war submarine. That the landlocked country has a maritime history might sound like an oxymoron, but it's not. A group of enthusiasts in cooperation with the Czech diving team has been mapping the traces of Czechs in the Austro-Hungarian naval fleet for a long time. They look for evidence not only in books, but also directly in the submarines that they find under the surface. They specialize in World War I, but they don't see the subjects of the study as just members of the military. They are interested in their whole stories, their relationship to the home and what they left in it. Together with hundred-ton machines, they uncover evidence of human courage, self-sacrifice and national pride.