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?!
Long ago, the treasure chest was a 
necessary item in any dungeon delve,
في الماضي، كان صندوق الكنز مادةً
ضروريّة لأيّ بحث ديماس
Die Schatzkiste, die für
Dungeon-Abenteurer unverzichtbar war,
Antes, los Cofres eran indispensables
para explorar los calabozos,
Antes, los Cofres eran indispensables
para explorar los calabozos,
Il y a bien longtemps,
Tanto tempo fa, il forziere era uno strumento
necessario per l'esplorazione dei dungeon,
Há muito tempo, o baú do tesouro era um
item necessário em qualquer masmorra,
Давным-давно