The anime adaptation of Rusted Armors, a multimedia project that first started with a stage play and a manga adaptation. The project focuses on the relationship between the gun-toting Magoichi — who is the leader of the Saika Ikki mercenary group — and the Sengoku era warlord Oda Nobunaga.

Following the conclusion of the National Middle School Tennis Tournament, 12-year-old tennis prodigy Ryouma Echizen sets out to the United States in order to further improve his tennis skills. While finding his own way to shine in the sport, Ryouma investigates a perplexing development: the circumstances behind his father's retirement from professional tennis. Known as "Samurai Nanjiro," Ryouma's father Nanjiro is a legendary tennis player whose career abruptly ended after the US Open finals several years prior. Though Ryouma has studied the final match extensively, there are still many gaps in his understanding—gaps that he would only be able to fill by watching the match in person. As luck would have it, a supernatural phenomenon transports the young prodigy—and his unsuspecting classmate, Sakuno Ryuzaki—back in time to that very event. Although the events that occur before the game seem normal at first glance, the appearance of the mafia soon complicates the mystery behind the retirement. Despite the bad odds, Ryouma must do everything he can to unravel the circumstances and prevent his father's career from ending.

These are witches who defend everyone's smiles and fight enemies through the healing power of music. These witches, opposite of those in the defense fleet, are idols known as the Music Squadron.

After the battle with the Witch Cult, Subaru travels back to Crusch's manor with Emilia, when he discovers, to his horror, that everyone has forgotten Rem. Earlier, she and Crusch were ambushed by the Sin Archbishops of Gluttony, Lye Batenkaitos, and Greed, Regulus Corneus. Although they fought fiercely, both ended up having their existences eaten by Lye. This caused Rem to fall into a coma, with noone but Subaru remembering her, and Crusch lost her memories. After learning what happened, a devastated Subaru commits suicide in hopes of going back in time to before the ambush to prevent it. However, it fails as he returns to after the ambush had already occurred. Subaru later attends a meeting with Emilia, the amnesiac Crusch, Felis and Wilhelm. After a heated discussion, they decide to continue their alliance. After the meeting, Emilia comforts Subaru as he grieves for Rem.