Assassin's Creed/Memory Block Six

After Al Mualim tells you that Robert de Sable is in Jerusalem, you receive your final equipment upgrade from him: sword expertise and five more throwing knives, bringing your total to 15. Head to Jerusalem to take out the ninth and final target.

Jerusalem: Middle District
The main street going west as you come into the city will take you straight to the View Point in the northeast of the Middle District. If you want to visit with Malik at the Bureau first, the View Point right on the border will be closer, just down the street to the southwest. Like always, climb your first View Point to put the rest on your map and get three Investigations under your belt before asking Malik for de Sable's feather.
 * Objective: Assassinate Robert de Sable

The View Point in the northwest is in an area with guards at its only entrance, but it's very easy to get in from the rooftops to the east. Be careful though, as there is a Templar in your way who will call for help the minute he sees you. Alternatively, you could just climb the building right next to the guards on their west, or use the Scholars you can unlock by performing a Citizen Save up the stairs to their northeast.

Investigations

 * 1) Eavesdropping: In the northwest corner of the guarded northwest area of the district, you'll spot three men having a conversation with a bench just south of them. You'll learn that Robert de Sable attends the funeral of Majd Addin today.
 * 2) Informer: Along the center of the western wall you'll find one of your brothers beneath a lightpost on the side of the street. You'll have three minutes to take out two targets. This is one of the easier informer missions, with a generous time limit and nothing difficult to contend with while you do your work. Head south down the street you're on, then bear southwest to the well where the washer ladies and the first target are walking around. Head back the way you came, but stay going northeast instead of turning back down the street with the informer in it. Climb the round building you see with the beggar woman in front, and take out the other target up on the roof. From there you can jump down to the courtyard below, right in front of the informer. You'll get a map showing where to join the Scholars to get into the funeral.
 * 3) Interrogation: In a large open courtyard in the center of the district, just north of the west side of the Poor District's border, you'll find a man preaching from the top of a staircase to a large building, with two guards below him. Follow him into the alley to the northwest and beat the speaker to find out that Robert de Sable will be at Majd Addin's funeral today.
 * 4) Pickpocket: Just to the west of where the three districts meet in the center of the city, you'll find a priest and a soldier talking together below a tree on the side of the street. Your target is the priest, who heads southeast around the building. You'll receive a map showing where all the guards will be stationed as well as Robert's position.

Informer: There is an informer just south of the huge building in the northeast. You'll have five minutes to take out five targets. Start out by going west to the first left, which will take you south directly to the first target. Keep going in that direction and take the little alley to your right (west). Tackle the madmen out of your way, and kill the second Templar near the intersection on the other side. Go around the corner to the east hugging the wall, which turns northeast to a carpet shop. Take out the next guy and proceed northeast up the stairs across the street. Avoid the madman at the top, and go after the Templar down the southeast alley. After killing him, keep going in that direction to the final target. You'll receive a map showing the location of Robert's men and the advice to not fight them all at once, but to come back and take them out one at a time. Pickpocket: Inside the big building in the northeast is a Templar talking to a soldier. However, both entrances are guarded and there aren't any Scholars to get you in. You'll have to climb up to the top and drop down to them. There are two guards at the top, unless you've already taken them out while scaling the View Point here. Once you get down, you'll find that the whole area is swarming with lunatics. It's best to target the two from above and wait for the soldier to start moving before jumping down and quickly making your way to him for the pickpocket. You'll receive a map showing the extra guards' positions and Robert's. 
 * Console version

Informer Informer 
 * Windows version

Assassination
Your target will be in attendance at the funeral of Majd Addin, who you assassinated the last time you were in Jerusalem. You can sneak in with Scholars, or just hop a far wall and walk into the ceremony. The Templars are ready for you this time, and you'll see de Sable indicating he knows of your presence to his underlings during the cut scene. Suddenly he'll shout that there is an assassin in their midst and the citizens will clear out. You have a couple choices here. You can stay and fight in the cemetery, or run out into the city to get away from the archers and try to take out your target when he's alone. If you stay and fight, consider heading up the ladder, as your enemies can't surround you, and you can use the ladder bottleneck to dispatch the Templars.

Whether you fight in the cemetery or the city, after you finally best the target and find out it was an imposter, you'll need to make your way back to the Bureau to warn someone. Your orders are to report back to Al Mualim in Masyaf, but Altaïr thinks it's more important to stop de Sable from uniting the two warring nations against the Brotherhood. In that case, you're off to a new destination: Arsuf.

Arsuf
When you get to Arsuf, by riding directly from Jerusalem or by warping to a nearer city like Acre first, you'll find that it's a long series of fights with the Saracens and English soldiers down a long path blocked by memory walls. You'll need to dispatch all the enemies before your memory synchronizes enough with Altaïr's to allow you access further into the memory. At times you'll be fighting huge groups of enemies, so patience and your counterattack skill will be extremely helpful in these fights. If you lose a lot of health, don't be afraid to wait around for your sync bar to replenish before moving on to the next area. Eventually you will fight all the way to Robert de Sable, in conference with King Richard himself.
 * Objective: Warn King Richard of Robert de Sable's plot

After informing the king of the plot against him and the other ruler, Richard will leave the decision of who to believe up to God, meaning whoever wins in a fight between you and de Sable. Before fighting your nemesis however, you'll be attacked by ten Templars. Use the same techniques as in the earlier battles, with just biding your time and using counterattacks to do your killing. It's even more important here to be patient, because you don't want to start fighting de Sable with a low sync bar.
 * Objective: Kill Robert de Sable

When you've dispatched the Templars, Robert de Sable will attack. The easiest way to beat him is to do a counterattack, and then unload all your throwing knives into him. You can't hit him while he's down with melee attacks for some reason, but you can take him out in one go without even exhausting all your knives if you stick to just throwing them. It's a bit anticlimactic, so if you're keen on finishing the fight like a gentleman, you'll need to perform six counterattacks against him instead.

When it's all over, you'll continue your chat with the king before the memory block ends and you're back in Abstergo.

Epilogue
You'll find that a rescue missions has been mounted on your behalf back outside the Animus, but unfortunately your saviors are overwhelmed by the Abstergo forces. Talk to Lucy after Dr. Vidic leaves, then head back to your bedroom. When you come out this time, you'll find the keycode to the conference center in Lucy's outbox. In there you'll be able to access another computer with some more email to peruse. When you're done, go back to bed and wait for Vidic to wake you up for the final trip into the Animus.