Deathknell Dungeon is a location in Professor Layton vs. Phoenix Wright: Ace Attorney. It is a small prison cell, in which possible witches are confined.
Plot[]
After the first trial, Espella is charged with the possibility of being the Great Witch Bezella. She is then locked away in the Deathknell Dungeon. Phoenix Wright and Maya go visit her in the dungeon the next day in order to interrogate her.
Spoilers end here