Part 1: Infiltrate
This memory will start aboard the Morrigan, which will need to be piloted to that green objective marker off in the distance – this is the fort at Anticosti we visited earlier.
Sail over towards this until you see a pair of ships. If you look at your mini-map, you’ll want to avoid sailing into their lines of sight! Your objective marker will update shortly thereafter and you’ll need to sail to a nearby beach area. When you arrive, dock the ship and head ashore.
As you move ashore, look for a fallen tree just to the north. Climb this and follow the path across the various bits and pieces here to reach a snowy ledge. From here we can continue along the set path until we reach the wall of the fort. Either climb the tree here to reach a higher section of the wall or climb the wall itself to reach the top and enter the main fort area.
Our purpose here is to locate the leader of the guards and pick pocket him. From our current location, you should notice two guard towers. Tranquilise the guard in the tower closest to you and then jump across to the tower. From here tranquilise the second guard and then make your way to the second tower.
Once you are at the second tower, note that there are stalkers in the bushes below. Fortunately, instead of going there, we are going to want to jump to the roof of the building nearby using the trees to do so. When you arrive, walk over and stand facing the large stone gate. If you haven’t detected the leader by now, activate your Eagle vision to spot him.
Dive into the hay bale below and wait for the leader to patrol up the stairs and into the building here. As he goes inside, sneak up behind him and pick his pocket for the map. Once you have it, go back outside, climb to the roof and backtrack across the towers to the wall. Climb to the top.
Part 2: Escape
Once you reach the top of the wall, you should see the Morrigan under attack and fortunately there is a jutting out beam nearby that we can use to dive into the water below. Do so and swim to the ship and interact with the wheel to start sailing!
Simply sail out of the red restricted area whilst avoiding the enemy ships (you can take them out if you want, but sailing away is much quicker!). Once you are out in the open ocean, the memory will end.