Daniel Hawthorne is an 18 year old with a mayor allergy to mana, as even simple diagnostic spells from doctors clog his throat, making him unable to fulfill his dream of being a hunter. Not like he cared anyway.  Even so, it gives him the ability to see the beautiful physical manifestation of mana around the world, even if it was from a distance. One day, while passing the New York Metropolitan Museum of Art, a dungeon break occurs, and everything goes downhill from there, starting with the fact that the safe building has a protection spell that'll kill him if he crosses through.