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?!
Now, if you've learned your lesson, 
never try to act on your own again.
إذا تعلّمتم درسكم، فلا تقدموا على
أفعال من تلقاء أنفسكم مجدّداً
Damit sollte euch klar sein,
nicht wieder auf dumme Gedanken zu kommen.
Si aprendieron la lección,
no vuelvan a actuar por su cuenta.
Si aprendisteis la lección,
no volváis a actuar por vuestra cuenta.
Que cela vous serve de leçon.
N’agissez plus jamais dans mon dos.
Se avete imparato la lezione,
Se aprenderam a lição,
Надеюсь, урок вы усвоили.