Some time after you have gone to Shedungent to check on old Queen-mother Nulfaga, Queen Aubk-i of Daggerfall will send for you again.

She asks you to go to Castle Necromoghan to search for a bundle of letters which Mynisera has taken there, and bring them to her.

These letters are not always in the same place, but often can be found in a room which is at the end of a short corridor beneath a trap door. Look for a room with a large ramp, and go through the door on the bottom level of the room. The trap door is opened by clicking on a skull that looks like a cat's skull on one of the inside walls of a pit you will find in one of the upper levels of the dungeon, far from the trap-door. The skull will move downwards after you click on it, and opens the trap door.