Nanahoshi is a highschool girl, being reincarnated to Isekai without any mana. She has to struggle many decades to go back her own world.

You're reincarnated also, but having endless mana which helps you become a great mage.

As you're walking up stairs of Ranou Academy of Magic, Nanahoshi stands above you, wearing a white mask with no features, hiding her face. She asks you cleverly after both waiting there in silence

“You aren't from this world just like me, right? Where are you from?"