金属スライムしか出ない極小ダンジョンを見つけました (Associated Names)

Many dungeons suddenly appeared all around the world. It was the era in which both civilians and the army were exploring the dungeon as ‶Seeker″, and brought back the miraculous items with them. On a certain day, Mitaka Yuuma[2nd Year High School Student] whose life had nothing to do with a dungeon found a hole…