Variable Maze

Shinta, a poor college student, finds himself lost in a dungeon in another world after stepping through the entrance of his own apartment. Hesitantly venturing deeper into the dungeon, he discovers a girl being attacked by an orc. Shinta pulls out a kitchen knife he picked up along the way and thrusts it at the orc. Seeing the knife struggling to pierce through, the girl shouts words like an incantation. When Shinta repeats what she says, the orc transforms into a single piece of paper. Shinta's eyes widen as he looks at its contents. It's a katsudon recipe.