In the near future, unknown mechanical beings descend on Earth, randomly fusing with humans in order to survive.

While most of them were harmless, some were often violent and would be used for nefarious purposes by equal-minded individuals, with the resistance group known as "ARMS" having to assess the situation before taking care of it themselves with their own Mecha-Ude.

Hikaru Amatsuga, an average middle-school student, ends up forced to cooperate with Alma, an extremely rare yet amnesiac Mecha-Ude bonded to his hoodie.

[8] It features the staff and cast returning to reprise their roles, produced by TriF Studio and directed by Okamoto, with scripts written by Yasuhiro Nakanishi, character designs by Terumi Nishi and Yoko Uchida (with mecha designs by Nurikabe), and music composed by Hiroyuki Sawano, Kohta Yamamoto and AWSM's Daiki.

[9] While the first episode premiered at the 28th Fantasia International Film Festival on July 20, 2024,[10] the series aired from October 3 to December 20, 2024, on Tokyo MX and other networks.