Arpeggio of Blue Steel-1
In the year 2038, most of Earth's landmass has been lost due to rising sea levels. Mysterious battleships that look like reincarnations of WWII vessels have started appearing around the world to dominate the vast new oceans, always surrounded by fog. These ships have been called the 'Fleet of Fog'. Not only are they in possession of weapons that are far beyond what humans have available, but they come surrounded by defensive shields which render conventional weaponry all but useless.
Human naval fleets have been shattered by this indomitable threat. The Fleet of Fog has driven humanity from the seas. Anyone brave or foolish enough to risk the sea comes under attack. In this perilous era, there is only one hope for human survival: the I-401, captained by Gunzou Chihaya.