The daughter of one of Japan's wealthiest families has tragically died. Cause of death? Getting so steaming mad over a fighting game that her body just couldn't take it. But that's okay, because she's been reborn in a fantasy world, as tends to happen in these situations.
Quickly striking up a friendship with a demon named Muramura, she uses her standard OP isekai cheat powers to put the hurt on the other monsters that have infested the frontier.
But it's just not enough! A rich girl needs a rich life, and this medieval era isn't cutting it. They say the local demon lord is holed up in her dungeon with a mountain of treasure. That much wealth would make things more comfortable for our haughty heroine, and so she sets off to conquer the labyrinth.
Let the roguelike struggle for riches begin!