Memory 8 - The Mentor's Keeper
Full Sync: Save all citizens under attack.
In order to start the memory, walk to the table in the Assassins' HQ and press B. This time you'll take the role of Ezio's ancestor - Altair.
After the cinematic ends, quickly run towards the enemies and start the fight.
You need to get to the hill top, where your Mentor awaits you. If you want, you can run there avoiding any fights.
But in order to get the full sync, you have to save four citizens first. They are marked on the mini map with black dots. First of them can be found to the left from the beginning of this level. Kill all Templar threatening him and the men will flee to a safe place.
To get to another victim, go to the village's exit and turn left. While walking along the wall you should see a black dot on the map.
Two further victims can be found on the higher part of the hill, to the left of the path. They stand near each other, so you should have no problems with finding them. After saving the last citizen, you'll get a message confirming the completion of additional mission.
Once you get to the keep on the top of the hill, select the hidden blade as your weapon and start climbing the wall on the right.
There is a guard on the top awaiting you. Kill him while hanging from the wall edge.
Another two enemies can be spotted at the op on the right. Kill them quietly, staying unnoticed.
At the other end of the wall you'll find gap, where you can jump onto a wooden beam.
Now just aim at your victim from here (LT) and press X to end this memory.