Tomodachi no Imouto ga Ore ni Dake Uzai - Volume 5, Prologue

Side story of Kyoukai Senjou no Horizon bundled with the first press release of the 1st, 3rd, 5th and 7th Blu-ray volumes of both seasons of anime.

This side story follows Asama, Kimi and Mitotsudaira aboard Musashi one year before the beginning of the main story, as Asama is considering to create a music band together with her two friends for the next festival in Aki, a territory under the governance of K.P.A. Italia.

The Northern Ice Fields had no boundaries.

The Winter Wolves hid within the snow, the Frost Tigers growled incessantly, and the roars of Giants echoed throughout the land. Many species struggled to survive in the icefield. At the same time, a baby White Dragon possessing the power of time broke out of its egg and opened its platinum-colored eyes.

Years later, the legendary Time Dragon appeared, moving freely between the endless past, present, and future.