After the revelation that ROSA is behind everything, the team will be free to look around. The SPROUT MOLES, fortunately, are poor jailors, and they left the gate open. You can walk right out and explore. You'll run into the following enemies exploring THE DUNGEON:

  • HAROLD - A SPROUT MOLE in armor. Can attack, as well as raise its own defense and make someone HAPPY. Not a huge deal.
  • MARSHA - A SPROUT MOLE with an axe attached to its side. Can hit pretty hard with melee attacks, but is a bit on the slow side. You can usually take these out before they get an attack.

Have a look around the narrow corridors. There are a few things to see:

  • To the left of the starting jail cell are a few jars. AUBREY can smash them up to find TOFU. Smash any other jars you find to discover more TOFU as you explore, if you... really want the stuff.
  • The jail cell next to the starting cell contains a toilet with RAMEN inside. That's still disgusting.
  • In the northern chamber you'll find a platform that KEL can climb onto. Use it to fling trash at a nearby switch, opening a cell to the east. This one seems quite pleasant, comparatively, though there's not much of use inside, besides a change of music. (This may be intended for a certain SPACE EX-BOYFRIEND. Perhaps?)
  • Check the southwestern cell. You can open it via a switch beside the door. Inside is a trapdoor leading beneath the floor. This is your way forward.

Through the trapdoor you'll find a narrow corridor. Head north and use KEL to hit a switch that will lower some spikes. Walk east of here to find a ladder and a southbound hallway. If you continue east you'll walk through the wall and find a second ladder, leading to a locked cell. You can unlock it from within, as well as find a tunnel in the hole in the wall, between the skeletons.

The hole between the skeletons leads to a grisly torture chamber, filled with... more skeletons. There are more jars to break, and the enemies within will happily fight you. (This is a good spot to grind levels, if you feel the need.) Check the upper-right corner of the torture chamber for a LIFE JAM, and the upper-left corner for JAM PACKETS.

Head back underground. Go south and MARI is on the other side of some spikes. She'll happily hit a switch and remove them for you. Picnic here, restore your health, and save, and if you need any items, go up the ladder near MARI. At the top you'll find a SMUGGLER JASH who will sell you an assortment of restoratives. Don't forget to pop open the smuggler's cell.

Head back down the ladder and take the right path out of MARI's little room. Follow the path east and south, until you hit a ladder. Go up and you'll be in a cell with a switch, as well as a toilet containing RAMEN. Hit the switch to lower the spikes in front of the cell next door. Inside it you'll find the I key for Hangman.

Head back to the basement and carry on south to find a switch only KEL can activate. It'll lower spikes near the ladder you originally came down, in the southwest corner of the area. Backtrack all the way back to the beginning of the narrow corridors and you can hit a switch that will blow up the SPROUT MOLE to the north. This will allow you to hit another switch, lowering the last set of spikes near MARI's room.

Go down this final corridor and you'll find TOFU, as well as a ladder. Go up the ladder and you'll be in the main hall of the castle. Go through the door to your right and you'll be back in the original, cell-filled area. Hit the switch in front of you to lower the spikes and create a direct path, in case you ever want to return here. Then head south in the previous hallway. (Note that it's actually worth destroying the jars in this hall, as they contains CLAMS, not TOFU.)