Plucking the Quill

Speak with Goodwin at The Nun’s Minster in northeast Wincestre. You'll have a cutscene with Goodwin and King Aelfred. Afterward, a child will ask if you found her mother's charm, which Reeve Selwyn may have taken. You can offer the child 115 silver or decline.

Follow the child through Wincestre. You'll find a guard bothering a child; assassinate the guard and speak with the child for information about the Quill.

The child will name two other children who know more. Use Odin’s Sight to locate them nearby. Speak with them to trigger a cutscene.

Find the children by the mill to the southeast and speak with them. Thugs will approach; you can either fight them immediately, pay them 230 silver, or convince them to leave if you have 4 Charisma.

After dealing with the thugs, speak with the children again. They will give you a key to the sewers and reveal the Quill's true name is Hilda.

Locate the sewer hideout south of where you spoke with the children. Use your raven to find the entrance and use the key to open the door.

Inside the sewers, move the barricade at the bottom of the steps. You can speak with the children behind it, but they offer no crucial information.

Turn south and slide under the hole in the wall. Kill the guards to proceed through the sewers. The Advanced Assassination skill is helpful here.

You will reach an empty room that triggers a cutscene, revealing that the child Aelwyn has been working for Hilda.

Immediately climb the wall to the west to confront Hilda, who is firing a crossbow. Defeat her quickly, as she is weak and has little armor.

Finish off any remaining guards and confirm the kill on Hilda to complete the quest.