Kenkouki: Hi no Kuni Dai Teikokugun Kurenai Ikkitousen-tai

A military superpower known as the Atrable Federation initiates the Endless War by conquering several neighboring nations and then targets the Great Empire of Sun, a small island country and the protagonist's homeland. A 17-year-old girl named Akiyama Maika searches for her father, who went to war when she was young. When the elite squad Ikkitousentai arrives in a nearby city, Maika hopes to find answers about her father. She learns he is not listed in the military records and becomes discouraged. While struggling with the harsh city environment, she witnesses a large man falling from the sky. Identified as the Invincible Wolf from the Ikkitousentai, he appears to know something about her father but refuses to share information with a civilian. Determined, Maika resolves to join the Ikkitousentai despite the army's policy against accepting women.