Arpeggio of Blue Steel
A mysterious fleet equipped with superweapons, "The Fleet of Fog", appears out of nowhere all over the world. Humanity is helpless against them, and is driven from the oceans. Seventeen years later, Gunzou Chihaya and his friends fight against the Fleet of Fog with the Fog submarine I401, along with the ship's "Mental Model", a human-like personality named Iona. The ultimate SF naval adventure!