On this page of the Assassin's Creed Valhalla guide, you will find a walkthrough of Sister of the Axe side mission.
Award for completion: 1200 XP.
In the place marked in the picture above, you will encounter women who have locked themselves in a small brick church.
You will find the key to the building right next door, near the tombstone. Take it, open the door to the church, and talk to the women.
The sisters are trying to develop a plan that will enable them to recover an item (cane) that the soldiers stationed in the nearby camp took away from them. Offer your help and follow the women.
Several soldiers are stationed in the camp. You can kill them quietly or eliminate them in open fight. Interestingly, if a bigger fight begins, the sisters will throw themselves into battle and start to shower the soldiers with their fists. The item related to the quest is in the possession of the soldier leader (with a shield and crank). After the fight is over, take the item from the body of a defeated soldier and follow the women to the river.
There you will have to fight a duel with 3 wolves. If one of the sisters gets knocked down, make sure you help her get up before you proceed. When you are there, talk to your sisters to complete the quest.