Seiichi and Saria train under Artoria to become adventurers. During their training the three of them are teleported into a dungeon by a demon’s trap.

The dungeon they find themselves in the stronghold of the Black Dragon God, the strongest member of the Demon Lord’s Army. Artoria gets separated from Seiichi and Saria in the dungeon and the giant Black Dragon God appears before her. Then that overwhelming threat attacks! Can Seiichi and Saria save her in time?!
It's an exceptional item that doubles 
my physical abilities during battle.
إنّه مادةٌ فريدة تضاعف قدرتي
البدنيّة مرّتين أثناء القتال
Die ist großartig, weil sie
die eigene Kampfkraft verdoppelt.
Duplica tus habilidades físicas
en batalla, es excelente.
Duplica tus habilidades físicas
en batalla, es fantástica.
Elle est exceptionnelle,
car elle double ma force en combat.
È uno strumento eccezionale che raddoppia
le mie capacità fisiche durante la battaglia.
É um item excepcional que dobra minhas
habilidades físicas durante a batalha.
Уникальная вещь, которая 
удваивает силу во время битвы.