ayvacs44,661 Locked 26 Dec 2023
In the Glen, get the wool from the shepherd and offer to trade it with the trader. Say "no" the first time; he will then offer you a shirt, and accept it.
Once you get to the Refuge, go to the alley and find the tree where Niko sees a fox. Go all the way to the right, equip the shirt, and interact with the wall that has a ram symbol on it. The wall will open. Walk inside and you get the achievement