Dungeon ni Deai wo Motomeru no wa Machigatteiru Darou ka III OVA

Sinopsis

There's a new natural hot spring in Orario thanks to the Dian Cecht Familia, but Naaza of the Miach Familia suspects an elaborate con and needs help to prove it. What does that mean for Bell since he's in the wrong place at the wrong time? It means getting caught in the middle of an ongoing rivalry between two Familias. Again. (Source: ANN)