Rie Nakagawa

The story follows three girls — Kaede Makidera, Kane Himuro, and Yukika Saegusa — at Homurahara Academy, but has nothing to do with the efforts to restore the Human Order.

At Yachimata, there is a legend of a deity named Tayutayu-sama who protected the area, but this deity and other so-called "Tayutai" have been lost in time. Mito and his friends discover a relic on the school grounds with mysterious patterns on it. Then, at the opening ceremony of the new school year, an equally mysterious girl named Mashiro appears before Mito. Mashiro is somehow tied to the relic and the legend of Tayutayu-sama.

In a post-war alternative timeline, Japan is divided into the North, controlled by the Union, and the South, controlled by the United States. A mysterious high tower rises within the borders of the Union. Three high school students promise to cross the border with a self-built airplane and unravel the secret of the tower.