Takeru Narihira is a lone wolf delinquent who spends his days getting into fights, avoiding friendships, and being captivated by a mysterious girl named Tsukimiya—someone he's only ever seen in his dreams. One day, a sudden accident sends him tumbling off a cliff. When he regains consciousness, he finds himself in Denji Heian-kyou, a futuristic version of the ancient capital, where advanced technology and mysticism coexist. This world is under the protection of the legendary onmyouji, Abe no Seimei—and to Takeru's shock, Tsukimiya is real and living in this very place. Just as he begins to revel in this fated encounter, a deadly black mist known as Yamikaoru descends, bringing forth monstrous beings called Oni. In the chaos, both he and Tsukimiya are killed—only for Takeru to awaken once again in Denji Heian-kyou. Realizing he has somehow slipped through time, Takeru resolves to defy fate. To protect Tsukimiya from her doomed future, he turns to Abe no Seimei to train in the art of onmyou-jutsu. Now, as an onmyouji himself, he must fight to rewrite destiny and uncover the truth behind this strange new world.

The third film in the six-part Girls & Panzer: Saishuushou film series.

The compilation film will recap the anime's 59 episodes from seasons one to three.

A lot has happened for Nagi Umino and Erika Amano: they were swapped at birth, learned of their engagement, and have started living under the same roof. The two now share their home with Nagi's sister, Sachi, and his crush, Hiro Segawa. Despite this unusual domestic situation and frequent quarreling, the group is beginning to settle into a life together. However, the return of Nagi's childhood friend Ai Mochizuki to Japan complicates things. Ai suddenly declares her intention to marry Nagi, and although he turns her down, she is committed to having him all to herself. Now with four girls around, each with their own thoughts about him, Nagi must figure out his own feelings and the best way forward.