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. (Source: ANN)

Twenty-six-year-old Hiroto Suwa; his wife, Naho; and their old high school classmates—Takako Chino, Azusa Murasaka, and Saku Hagita—visit Mt. Koubou to view the cherry blossoms together. While watching the setting sun, they reminisce about Kakeru Naruse, their friend who died 10 years ago. Mourning for him, they decide to visit Kakeru's old home, where they learn the secret of his death from his grandmother. Filled with regret, Suwa and his friends decide to write letters to their 16-year-old past selves to set their hearts at rest. With the knowledge contained in the letter from his future self, 16-year-old Suwa has the chance to rewrite the future. What choices will he make? What will happen in this new future? [Written by MAL Rewrite]

Shintarou Kisaragi—a NEET who shut himself inside his room for 2 years—has been living his life normally until he met a cyber girl named Ene, who appeared in his computer screen when someone anonymously sent him a mysterious e-mail one year ago. One day, Ene had been messing with Shintaro's PC, which causes him have to go to the outside world for first time in two years. (Source: Official site)

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.," This is 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 starts to reveal why the war began and her reason for siding with humanity. [Written by MAL Rewrite]