Lady Mhoire Quest
From Drunkapedia
During night time in the Graveyard, Lady Tairla Mhoire will rarely appear in the open (people who hunt Graveyard regularly will see her perhaps once or twice a month). Kill her then talk to her shade that appears (several people can talk to her) for a key that opens the Sealed Vault in one of the bunkers. If morning comes before she dies she will disappear.