While on the road to their field trip, Class 2-C's bus is enveloped in light, and the Goddess, Vicius, summons the students and their teacher to another world. The Goddess hopes to raise them as Heroes to defeat the Great Demon Empire, and she welcomes the students after appraising their abilities with her crystal. However, Mimori Touka is appraised as an E-Class, the lowest rank... and he's branded a trash hero.
If I make it back alive, 
you'd better be ready for me.
‫إن عدت حيا،
Mach dich auf was gefasst,
wenn ich zurückkomme!
¡Si vuelvo con vida, prepárate!
¡Si vuelvo con vida, prepárate!
Si j’en ressors vivant,
je te conseille de te préparer.
Se riuscirò a tornare vivo,
Se eu conseguir voltar vivo,
Если вернусь живым,
то ты у меня поплатишься!