On this page of our guide for Assassin's Creed Valhalla you will find a detailed walkthrough for the Razing Earnningstone mission.
Eivor joins Galinn and his crew to raid the settlements loyal to Wigmund together. In this way, Eivor can get the information he needs to make it clear whether Galinn is a traitor.
Rewards: 1700 XP.
Speak with Galinn
Galinn is planning to raid Earnningstone and together with his people they set up a small camp near the settlement. During the conversation you can ask Galinn what he thinks about Soma, her clan and her inner circle.
Galinn's plan is simple - all the counties in the region support Soma and her clan, except for Earnningstone, so it should be plundered.
The greatest progress in the mission is achieved by burning houses. Once the progress bar reaches 100% this stage of the task will be successful and you will be able to talk to Galinn again to complete the mission. As a reward you will receive 1700 XP.