Assassin's Creed IV: Aveline Walkthrough Part 1 – “The Rebel Camp”
Head on up the slope in front of Aveline. Continue straight forward into the scaffolding. Swing across the gap with the pulley arm then climb up the wall and start shimmying to the left. When you reach the pole sticking out swing forward and Aveline will automatically jump to the ledge when she has enough momentum. After that continue over to the left. Keep this up until she climbs onto a wall with another opposite it. Back eject onto it and continue on upwards. On the platform jump across to the suspended platform and continue on to the left. Before too much longer you will find a pair of guards attacking a Slave. Move in and take them down with a Double Assassination.
Head to the left after the talk with the Slave. Once Aveline hops the log look to the right. You will see a tree she can run up. Do so and head across to the next branch. Go to the end of it and perform a Leap of Faith into the hay stack below. Wait in there for a minute so the guard comes wandering by. Whistle to lure him in and kill him. Your goal now is to make to the House in the middle undetected.
When the guards have their backs turned cross over into the nearby Stalking Zone. Dart up from there over to the house. Take out the guards, disable the bell then liberate the Slaves. This will trigger a cutscene. After that take out the remaining guards in the area to stop the alarm from being raised. The easiest way to take them out is to climb onto the nearby house and use Darts and Aveline's pistols.
Head to the North of the house and then use the Free-run course to get to the Northern search area. Once inside it, duck into the Stalking Zone just behind the Western house. Use Sleep Darts on the Guard across from you and the Gunner on the roof. This will let you cross over to the Northern side of the area without incident. After that you can easily approach the prisoners. Just assassinate one and hit the other with a Sleep Dart. Knock him out then free the Second group of Slaves.
There is one search area left to the South. Head straight there and go over the fence. Take out the guard patrolling the perimeter first. After that climb up onto the House and use it to mark the other Soldiers in the area. To the South you another set of patrolling guards. To the East you will find a pair of Soldiers watching over the Slaves. Just deal with the remaining guards through combat and then liberate the Slaves to learn of your next destination to the North.
Head to the Northern end of the area, just outside the Restricted Zone. Move to the Northern part of the Restricted Zone and take out the guards there. Continue to the North after that. You will see a man on a bridge ahead. This is the Captain. Use Eagle Vision to identify him then it is time for a chase.
Go to the left of where the bridge was immediately and use the free run course there to get across. After that just favor the right and follow the course as presented. While you can catch up to the captain, you cannot tackle him. Instead you need to follow him to a cliff. There he will turn and fight you. Take him down.
Now just head on out on the branch to the West and perform a Leap of Faith into the water below. From there just swim to the West and climb into the fort using the free running course just out of the water. Watch the closing scene to see what happens.