After Vault 13's last water chip breaks, the Vault Dweller is sent out to find one. A few citizens of Vault 13 are becoming restless, wanting to go to the surface, thinking that the machinery in the vault will break eventually. These characters are affiliated with Theresa and are part of her rebel faction in Vault 13.
As well as providing information through conversation these dwellers will help the PC with some quests. If the player tells them that the search for the chip is not going well but advises them against leaving, they invite the vault dweller to a meeting with Theresa at 1700 hrs every evening.