You'll start up right at the ending of Assassin's Creed 2. During this mini tutorial, you'll be lead and instructed by Mario. Turn on your Eagle Vision and you'll be shown the path to climb up the shaft. Once arriving on the top, follow Mario and you'll soon be swarmed by members of the church. They mean you no true harm, so simply pushing them out of the way will be enough to let you exit the chapel.
Outside won't be as clean and you'll need to kill several guards. Mario will help you with some distractions, but it's mainly up to you to finish of the soldiers. Normal attacks are good enough, but consider using more tactics, such as counter attacks or grabbing the enemy. One of the best ways to deal with the foes is to kick them in the shins, lowering their defenses. Further, you can out right kill them simply by kicking them an absurd amount of times. No point in being stealthy if you have even the toughest enemy trapped in a stun lock.
After the initial enemies are dealt with, keep following Mario over the roof and dispatch any more enemies that come your way. You'll soon reach the top of a tower and over look the vast scope of Rome.
R & R
You'll return to Monteriggioni--the base of operations from the previous Assassin's Creed--and several of the town's folk will need assistance with a few tasks. This, like most of the first Sequence is a basic tutorial of how to perform average events.
You can do these in any order, but the woman in the town square will be the closest. Talk to her and then carry her box for her. Follow her to just outside your manor to complete the Memory.
The next Memory you can complete involves catching a run away horse. Head outside the city's gates and talk to the man outside.
It's another simple task of running up to he horse and using your actions to ride it. Just wait for it to stand still before dashing at it. After mounting the horse, return to the NPC to complete the memory.
Climb the walls of the city and you'll find a few guards manning a cannon. One of their comrades has decided to wonder off and take a nap. Follow the markers on your map and wake this dozing soldier.
Return to the cannon and you'll be given the task of operating it and having some target practice. Shoot and destroy five of the dummies to complete the Memory.
After all of these Memories, return to the manor for a few cutscenes. you'll awake the next morning under attack by the Borgia army. Rush outside and on to a horse, ride it until it is crushed by the falling debris.
Next, head up the city wall from the previous Memory. It will quickly crumble, requiring you to restart your accent to the top.
Man the cannon from before and use it to destroy the enemy Borgia armaments. There are too many soldiers and siege weapons to clear the whole field, however you only need to destroy enough to allow time for the citizens to escape. Afterwards, abandon the cannon and head across the city walls and up the tower. You can get in one free kill, so use it to finish off one of the stronger soldiers. Most of the enemies can be killed with simple counters or grabs. However, several heavy armored units will also appear. For these heavy brutes you'll need to resort to kicking them in the shins until they die.
Regroup with the friendly soldiers and battle your way to the manor. Your allies can fight just as well as you. If you want, disengage from your foes and let the Monteriggioni guards fight for you while you sprint away.
You'll encounter Claudia who is in need of rescuing. Kill the Borgia soldier trying to stab her and escort your sister to the back of the manor. There are other enemy soldiers along the way, but your allies will keep them busy. Enter inside and you'll meet up with some thieves and scouts, ending the Sequence.
You'll be in control of Desmond for this portion of the game. Unlike Ezio, Desmond has no life bar so he takes no damage. There is also no combat element, despite him being equipped with a hidden blade.
Right from the start you'll spot a ghost of Ezio fleeing the manor. Follow it to the right and leap off the plank to the hay pile below. After a quick scene of you and Lucy checking a dark cave, you'll find that you're underground. Press the switch ahead to let Lucy pass through the gate. You'll need to find your own way through, so climb the ledge to the left and proceed forward.
Dive down to the water below and swim to the highlighted switch, this will lower one bridge, while raising a second and allow Lucy to move forward. Return to the surface and shimmy across the planks above the new accessible platform. Drop down and there will be a second switch, allowing you and Lucy to continue forward.
In the next area there will be a gap that is too great for you to cross on your own. Stand on the platform ahead and give Lucy a boost across. She will lower a device that you can use to leap across.
Ascend the wall to the left and you'll come to another switch behind a gate. You however crawl over the wood frames to the right and then leap into the small room behind the gate. Flip the switch and continue across the rocks on the bottom. After a short scene of discovering a huge room and setting up the Animus, use Eagle Vision and examine the triangle drawing on the wall. While in vision mode, you'll see hidden numbers behind the drawing.
You'll discover that Monteriggioni doesn't have working power. Exit the manor and talk to Shaun. You'll need to interact with several fuse boxes to start up the power. You can use Eagle Vision to help spot the boxes better. After all of them are started up, meet with the rest of the Assassins to start up the Animus.
Before starting the next Sequence, Rebecca will advise trying out some training missions. These aren't mandatory, but they can help you better understand the combat and stealth mechanics of the game. You can also use the Animus' DNA system to replay completed Memories from Ezio's past.
As good as New...
You'll be injured during your escape from Monteriggioni and return to Rome. Use your map to seek out a doctor and heal yourself for $50. If you want to acquire more money, consider stealing from the Roman citizens.
After restoring your health, follow your map marker and climb the building. On the roof you'll get a clear viewpoint to your next goal. Dive down to the hay below and look for your next mark.
Follow the guards and keep your distance. If you get too far a timer will start, showing you that you're about to lose them. Likewise, you can't get too close or they will attack, failing the Memory. They'll move to the gallows, where they will attack a grieving citizen. Kill the Borgia guards by kicking them in the shins or grabbing them to finish the Memory.
After rescuing the citizen, he'll ask you to kill the executioner that killed his wife. Follow the marker on your map and you'll find the Borgia executioner.
Sneak on top of the roof and get the executioner into range. When no one notices you, you can get a free instant-kill via the assassinate prompt. Use it and then flee the scene. There is no need to kill anyone else, so don't bother with necessary combat.
New Man in Town
Meet with Machiavelli and he will ask you to take care of a few people for him.
Your gear in shambles though. Head to an armory and purchase some new spaulders. If the shop is closed off, spend some of your money to restore it. Likewise, if you are strapped for cash, steal it from the citizens. Move to the restricted area and discover your target, a Borgia captain.
Move to the highest point and get in a few free kills with your assassination move. This will allow you to easily kill off the captain while his men are dispatched. With the captain dead, you can also take the time to destroy the Borgia tower and remove the area's restriction. Return to Machiavelli to end the Memory.
Easy Come, Easy Go
Grab a horse and follow Machiavelli. You'll need to rescues a citizen who is being harassed by the Borgia. Both your allies are capable fighters, however they will still need your support, especially against any mounted combatant. If the Borgia steal a horse, be quick about dismounting them and making the playing field more even.
Crepi Il Lupo
You'll discover a Borgia Messenger fleeing the scene, chase after him and use a tackle to steal his information. Try to resort from violent means, as killing the messenger could alarm the rest of the Borgia guards.
Meet up with Machiavelli again, or so you may expect. you'll instead be ambushed by the Followers of Romulus. Use your hidden blade and shin kicks to fend them off. If you need, stop and grab a healing kit and restore any lost life. Once all of the Followers are dead, move to the sewers below and discover their hidden base.
The Halls of Nero
You'll be traipsing around the underground of Rome. Move up the pillars to the left or right and flip the four switches. You can shimmy and leap across to all four instead of leaping across the center. Once all four switches are one, the floor will break. Leap down to the lower level.
Move behind the gates and climb on top of the pillars. Leap to the walls and shimmy across the wall and move to the plant over the gate. Next jump and swing across the light, landing behind the next gate ahead.
After leaping across a few more gates you'll come to a room filled with fire. Climb over the statue in the center and move across the wall on the left. Once again, leap to the next statue to clear the flames. Shimmy and climb the next wall on the left and you'll discover a new room. Climb across the next set of walls and some will shatter, leaving a new means of cutting across the maze.
Jump across the beams and you'll soon make it to the main hall. Run up to the stone throne in the distance and jump to the left side. You'll need to circle all the way across the room and back to the right end. Every so often some of the pillars will break, adding shortcuts in case you fail some jumps. Also stop to grab the Borgia flag that is stationed on the right side of the room.
When ready, enter the Followers' stash and steal all of their money. In the center of the room is an also a scroll. Snatch it up and exit through the hatch at the top to finish up the Memory.
You'll need to rescue a courtesan that is being held for ransom. Gather up $2500 by either stealing or withdrawing from the Roman banks.
Either way, head to the docks and deliver the money. The area is a restricted Borgia zone, so be careful to not alert the guards. After a brief scene, kill the pirates. Your hidden blade will surface, but also consider stealing their weapons and using them against the enemy.
Afterwards, return to Claudia and inform her that the negotiations went south. Afterwards, talk to the architect and restore the area.
You'll meet up with La Volpe and will need to convince him to rejoin with the Assassins.
Follow him and move to the marker on the map. You'll view some thieves who will get in trouble with the Borgia. Rescue the young man by killing all of the Borgia in the area. All of them are using ranged weapons, so consider using some of your own. Also, their slow loading crossbows and guns make them open to quick melee assaults.
Escort the wounded man to safety, each time stopping to kill or elude the guards. If your infamy is still too high, find a politician and kill them off. Afterwards, go to your map marker to meet with La Volpe again and restore the area.
Between a Rock and a Hard Place
Meet with Bartolommeo and you'll find that he and his men are being harassed by the Borgia troops.
Hunt down the Borgia captain, leaving your allies to deal with the fodder. Sneak up to the captain and kill him with a quick assassination. Free the region of Borgia control by moving to the Borgia tower and destroying it.
Return to Bart and watch a few scenes. After talking to Machiavelli again, meet with another architect to finish the Sequence