Lupin, the phantom thief, is dead. At least that is what everyone believes. But rather, a certain incident will drag Lupin back from Hell after his assumed death. For he has been taken completely by surprise by being deceived through a trap called "love," in a string of incidents that began with a heist of 4 million pounds sterling of gold coins.

By 2039, global warming had caused sea levels to rise and large amount of territory to be lost. As though in response, a mysterious group of warships clad in mist, “the Fleet of Mist,” appeared in every corner of the ocean, and began attacking human ships. In spite of humanity mustering all their strength, they were utterly defeated by the Mist's overwhelming force. All of humanity's trade routes were blockaded by the Fleet of Mist, their political economy was destroyed, and the human race was steadily beaten down. Seven years later, the Fleet of Mist's submarine I-401 appears before cadet Gunzo Chihaya. The humanoid life form that pilots the sub, who should be their enemy, is instead offering her services to mankind.

The group of privateers known as the Blue Steel continues their mission to deliver blueprints of the Vibration Warhead Torpedo, a weapon that may turn the tides of war in their favor, to the United States. However, a new threat arises from their enemy, the overwhelming Fleet of Fog in the form of "The Student Council", a group of warships composed of the remaining Mental Models, the ships' humanoid avatars, who have yet to face the unpredictable captain of the Blue Steel, Gunzou Chihaya. As the Blue Steel gets closer to understanding the origins of the authority controlling the enemy, Iona's past reveals the beginning of the war and her reason for siding with humanity.

Recap of the Aoki Hagane no Arpeggio: Ars Nova TV series, with approximately 40 minutes of new material. By 2039, global warming had caused sea levels to rise and large amount of territory to be lost. As though in response, a mysterious group of warships clad in mist, "the Fleet of Mist," appeared in every corner of the ocean, and began attacking human ships. In spite of humanity mustering all their strength, they were utterly defeated by the Mist's overwhelming force. All of humanity's trade routes were blockaded by the Fleet of Mist, their political economy was destroyed, and the human race was steadily beaten down. Seven years later, the Fleet of Mist's submarine I-401 appears before cadet Gunzo Chihaya. The humanoid life form that pilots the sub, who should be their enemy, is instead offering her services to mankind.

Two teenage Mexican-American loners in 1987 El Paso explore a new, unusual friendship and the difficult road to self-discovery.

在21世纪初，人类因全球暖化的影响而失去了大半的陆地。此时，在世界各地突然出现了搭载着神秘超兵器、真面目不明而被称为“雾之舰队”的战舰群，对其毫无招架之力的人类失去了制海权，并且再也无法自由航行于大海之上，令人类的文明和繁荣大幅衰退。 人类虽然失去了制海权，但并未放弃重新成为海洋的主人、在海洋上自由航行的打算，一直谋划著对“海雾舰队”反击的“大反攻”之日。 17年后，原士官候补生千早群像与其同伴们在不知觉中搭上了潜水舰伊401，并与伊401的心智模型伊欧娜一起接受突破“海雾舰队”的海洋封锁、运送人类反击的希望的委托。