The Grand Bell Prisons (大鐘堂地下牢, daishoudou chikarou?, lit. "Grand Bell Dungeon") are the underground prisons located in the basement of the Grand Bell Hall, destined mainly to traitors and political adversaries of Metafalss's current rulers.
(more coming soon...)
While the Prisons are initially a section of the Grand Bell Hall itself, during the events of Phase 3 an earthquake causes the collapse of the entrance that leads to them, after which they are considered their own place apart of the Hall. This place is the smallest dungeon in the game and has no random encounters or Talk Topics, but it still has a few treasure chests and an IPD that has to be defeated in order to proceed. Since the exit to the Grand Bell Hall is obstructed by rubble, the only entrance and exit to this place is through the Moon Culvert.