Free Ghoul prisoner is a side quest in Fallout.
The quest for the water chip nears its end at the Necropolis. The Vault Dweller can show mercy to a ghoul kept prisoner by the Unity garrison by releasing him from his cell.
- Enter the Watershed's pump building. After negotiating the way through Harry and his garrison, locate the ghoul at the end of the building, beyond the water tanks.
- Lockpick the cell door or blow it open with an explosive.
- The ghoul will reveal that the manhole in the room by his cell leads down to Vault 12 and the water chip.
- 500 XP and the water chip's location.