The Mandolin Church Catacombs, also sometimes referred to as the Mandolin Church Grotto, are a dungeon area within Ritardando's Mandolin Church. The area was originally conceived as a shelter from pirate attacks from the Blues Sea, but has since been inhabited by monsters.
The party travels into the Mandolin Church Catacombs to investigate after the villagers report noises that they think could be ghosts. Allegretto, however, ditches the party to retrieve Polka from Tenuto Village, claiming that he is scared of ghosts. The remaining party makes their way deep into the dungeon, where they discover that the source of the noises was not ghosts, but rather a particularly fearsome monster. Upon finding that it is just a monster and not ghosts, they work together to defeat it.