Full Synchronisation Requirement - Do not be detected.
After listening in on the Templar’s conversation, it’s time to start exploring the underground cistern. Firstly, follow the ceiling beams along then drop down, and use Eagle Sense to easily locate some of the hidden gold treasure chests. These are numerous in the secret areas such as the Yerebatan Cistern, and usually contain rare bomb materials. Loot them if you wish, then follow the objective marker, scaling the scaffolding then jumping from beam to beam to reach the open hole in the stone. Drop down, swinging from the metal beam that spans the room, to find an oddly out of place Bomb Making station and more chests. In the next room the challenge inherent in getting full synchronisation in this Memory presents itself. The key to the next chamber is located on a patrolling Templar captain, surrounded by a plethora of guards, and getting it undetected is going to be tricky. However, there’s one important trick you can use to your advantage – killing the captain, even from afar, will grant you the key somehow on his death. Although at this point in the game it’s unlikely you have the crossbow, even the ranged poison will work well at this stage.
For the first captain however, heading to the right and taking out the patrolling guard is a good starting point. Hide his body in the water behind you, and then wait behind the pillar for the captain to move behind the wooden scaffolding to your right. Follow him and take him out with the hidden blade, then make your way slowly and quietly to the exit door.
The second chamber is a little easier to do with the use of silent ranged weapons. Make your way across the water-filled gap and past the patrolling spear guard, and head up the stairs. Once you reach the second floor, kill the rifleman with your hidden place and you should be able to shoot the captain on the scaffolding with poison. Then, simply make your way to the exit and wait for him to die, the key being magically added to your inventory.
Alternatively, you can continue up the tiers of the stone structure, taking out the patrolling guards as you go to reach a point above the captain where you can drop onto him with an air assassinate. However, if you choose to do it this way, be careful not do the ‘High Profile’ air assassinate, as it can cause the scaffolding the captain is on to collapse, giving you away and thus ruining your chances of getting full synchronisation.
In the next room a lone Templar awaits, along with a few more treasure chests. However, if you’re trying to stealth your way through this whole Memory it’s probably best to replay it later for the treasures. Continue to the objective marker to reach the final chamber and perhaps one of the hardest stealth segments in the whole game. Start by taking out the lone patrolling guard below you, and then use his body to lure the others away from the central island. Make your way around the outside of it to the left, hopefully avoiding confrontation. If you do get spotted however, walk slowly away or quickly take out the guard with ranged poison if they’re far away or with the hidden blade at close range to try and desperately avoid the alarm being raised. Similar to the last chamber, it’s possible to use ranged poison to kill the captain from the outer rim of the room, and then simply make your way to the exit and wait for him to die. When you get through the locked door, give yourself a pat on the back and loot the treasure chests, before using Eagle Sense to examine the glowing parts of wall. When you find the right one, head through and take the first Masyaf Key of the game to finish the Memory.