The movie is the story of the construction of Aizuchi castle. The castle was real, it was completed in 1576 and destroyed in 1585. It had for its time many innovations compared to other Japanese castles, for example thick walls of stone in defense of cannon fire.Okabe (Mataemon), the builder and Oda (Nobunaga), the warlord for whom the castle is built, were real historical people. The castle's name also used to name the era the Azuchi-Momoyama period (1568 to 1600).

The English title has been called "Castle Under Fiery Skies".

Somabito appear in this movie. They are strange and somewhat semi-religious wood cutters who have a kind of mysterious role in the forests. Some theories hold that they were vanquished Ainu who sought refuge in the forests long ago.