This quest begins immediately after The Measure of a Norseman. You’ll need to speak with Oswald, who can be found by the docks in Northwic. A cutscene will begin, during which Brothir presents the body of a spy belonging to Rued’s clan. You’ll have a couple of dialogue options here, but none have any significant impact. When the cutscene ends Eivor will be tasked with finding any other potential scouts around the walls of Northwic.
Find and Capture the Scout
Use your raven to identify the first area to the northwest. You can take the small boat from the docks and row to the location of the first scout, by the shore just beyond the bridge. Fight the scout and beat them to the ground. You can them tie them up and place them on the small boat. Bring them back to Oswald for questioning. You’ll have a few dialogue options here, but each lead to the same outcome. Even if you choose to spare the spies life, Valdis will take it.
Once Oswald decides to meet Rued in open battle, there will be no changing his mind. You must now travel southeast and meet with him. If you’d rather not travel over land, you’ll find a swift route along the Wensum River to the eastern coast, by which you can head south to the fortress of Dunwic. After a brief cutscene you will be tasked with infiltrating the fortress to light the brazier, killing any of Rued’s warriors along the way. If you want to avoid a large battle with a lot of warriors, you’ll benefit from entering the fortress by the secret entrance to the southwest.
Infiltrate Dunwic Fortress
To reach the secret entrance, make your way to the bridge and then walk along the rope on its right side. This will lead you directly to the entrance without being seen. Once inside, you’ll need to move the barricade to go deeper. Loot everything you can as you go and continue through the tunnels until you find a ladder to the north. At the top of the ladder you will find a guard to the southeast. Take them out and proceed up the steps to the south, taking out the guard on the platform above you with a swift arrow to the head as you go.
At the top of the steps you’ll find a Woe-Bringer. They should remain with their back to you while you’re undetected, so take advantage of this by shooting them in their weak points. Finish them off with a few high damage abilities, and round up any guards that might have been alerted to your presence. Looting the Woe-Bringer will provide you with a Nickel Ingot. When all the guards in the area are dead, free the woman from the nearby cage, and the man in the cage above you, then take the Dunwic Door Key from the nearby table.
To reach the wealth beneath you, take one of the nearby fire pots and throw it on the rubble blocking the hole. Jump down and move the barricade, revealing a door that you can open using the key you looted from the table upstairs. Once inside you will find a Book of Knowledge which grants the Rush & Bash ability, or grants it an upgrade if you already have it. You’ll also find a small treasure chest on the other side of the room. Now that you have the most valuable loot in the fortress, climb the eastern wall of the fortress (facing the sea) to find an Opal in a broken segment of it.
From the top of the eastern wall you will be able to see the brazier if you look down to the northwest. Once you’ve killed all the guards, all that remains is for you to light the brazier with your torch. A cutscene will begin and you’ll have a few dialogue options. Once again, all lead to the same outcome: Oswald fighting Rued. You can’t influence the way this plays out, so just watch on until it’s time to flee west with your allies. Meet them at the quest marker to go through some dialogue (again, all to the same outcome) and complete the quest.