Assassin's Creed 4: Black Flag Walkthrough Part 4 – Sequence 2: “... And My Sugar?”
Full Synchronization:
Hire Dancers to distract Guards
Stay out of combat
Head on back to the dock and talk with Bonnet. Apparently that fight got the Spanish to confiscate the items that Edward took of Duncan and Bonnet's Sugar. This means you need to tail the fellows with the sugar to learn where they've taken everything. Set off after the guards. Immediately activate Eagle Vision (L3 or Click Left Thumbstick) and tag the soldiers. Move up to the nearby group of Dancers and hire them. This gives you a mobile blending spot so that you stay out of sight and cannot be detected as long as Edward is hiding amongst the girls. When the soldiers head into an alleyway with 2 Soldiers at its entrance, start over to the left of it. You can catch up with them on the far side. This will lead you to the next restricted area they enter. Once again, you can hide amongst the girls. Do not follow them in, instead go around the building. You should have little trouble keeping up with them.
Things get interesting after a short while. It is apparent that the hanging will start soon. They want to hurry there. This means they will start running. Chase on after them. You do not need to worry about stealth for this part. Just keep pace with them. When they hop down then make a right past a haycart, that is when you want to worry about stealth again.
The soldiers have plenty to talk about and Edward needs to stay out of sight. Look for and hire the nearest band of Dancers. They will provide a mobile blending opportunity for Edward. This will get the men off Edward's scent. Follow them forward to the hanging. From there, head over to the left. You have a new target to tail: The Captain.
Follow him as he walks away from the hanging. When he enters the Restricted area, just wait outside for him. You have a need to follow him and watch for him to start looking at a stall. When he does, move in close and pickpocket him This will update your objective and give you the next one, as well as the next optional objective to stay out of combat.
To get into the Castillo and over to the lockup, you need to dismiss any Dancers you still have on you. Head over to the West from the plaza you stole the key. You will see a pier right next to the Castillo that you want to break into. Hop across the pylons sticking out of the water and get over to the door that is nearby quickly. There are Gunners on top of the wall. To avoid being spotted you need to quickly move against the wall and get over to the door.
Get against the corner by the door and then perform a corner assassination on the guard who walks out from the door. Head through the door and go to the right. There is a second guard just around the corner. Take him down as well then head into the room beyond him. Go past the powder and through the window on the left. Jump out onto the plank then move to the wall. Climb up and over to the right. Make your way on up to the next ledge.
On the ledge, wait for the guard to come to you. Ledge assassinate him then you need to check the 2 Sentries who are to the left and right of the break in the ledge. When they are both looking away, climb up and head to the marked door. Interact with it to get inside.
Now you just need to get away. Head on over to the right and jump of the battlement into the sea below. From there you just need to get over to the docks where Bonnet is waiting. Once there you will find the end of the memory.