Aoki Hagane no ArpeggioArpeggio of Blue Steel; Арпеджио Воронёной Стали; สงครามเรือรบสยบโลก; 苍蓝钢铁的琶音; 蒼き鋼のアルペジオ; 蒼藍鋼鐵的琶音; 푸른강철의 아르페지오; ლურჯი ფოლადის არპეჯიო

Suddenly, a fleet of ships with mysterious superweapons called the “Fleet of Fog” appeared all around the world. Humanity didn’t have the technology to fight such a fleet, so they were driven out of the sea... Seventeen years after the battle, for some reason, Gunzou Chihaya and his crewmates aboard the I-401 and the personification (Mental Model) of the I-401, Iona, started fighting the Fleet of Fog...