Starts in Havana.
This chain of memories begins in South Havana. The initial objective is simple if hard to do: Survive. Rhona's Bureau has come under attack from Templar Mercenaries. Edward arrives in time to help her defend the location from the gathering forces. The good news is there are powder kegs you can move into the openings in the walls to help defend the area with explosives. The bad news is you do no get to do this for the first one.
The first wave is not too hard to get through. A good Kill Streak will get you through it without any trouble at all. Between the first and second Edward is encouraged to move some of the explosive barrels into position. You want to get at least into the Northern, Southern and Eastern entrances to the yard. When the second wave begins, shoot whichever barrel has the forces incoming the soonest. It is unlikely you can get more than one shot off before you are back in combat.
Between the second and third wave you can go out and kill off the forces before they come at the yard. This is a great way to thin the ranks. The problem is you must stay close and you need to work quickly. This can remove a group of Soldiers from the wave without much effort. Just return to the yard before the timer expires and reload your pistols. Kill off those who come charging in.
There are a total of 4 waves you need to cut through. After that the mission is complete.