Complete mission walkthrough:
You will have to start off by watching a very long cut-scene (#1). You wouldn't be able to skip past it, however a lot of interesting things will happen during its course. Once again, you'll be playing as Captain Barbossa. Your main objective for this part of the mission will be to find Jack Sparrow and rescue him. You'll probably notice that you won't be allowed to leave the mission area. If you try to go somewhere else, you are going to be attacked by the hands of the undead (#2). Each of these hits will take two points from your health bar, so I wouldn't recommend experimenting too much. Stick close to the main path and you should be fine.
Start off by going towards the right edge of the screen. Ignore the tornados, because you won't be interacting with these objects. Destroy a single crate and move on. You will find your first crab pendant (#1) in the second crate. I think it's obvious that you need to pick it up. You are going to be attacked by the first group of the undead creatures very soon (#2). This isn't going to be a difficult fight, however you can't lose too many health points.
You should be able to reach a very large skeleton in just a few seconds (#1). Keep moving right. Remember that you shouldn't try stepping on the sand. Instead of being attacked by the undead, use the sword to attack one of the bones (#2). This will trigger a short cut-scene.
You will be able to use the bone in order to reach the next section of the map. I've also like to remind you to not go to sand areas. You will come across a crate. Destroy it and pick up a few gold coins. Keep moving right. A second group of monsters will be waiting for you here (#1). Thankfully, you won't have to worry about the invisible walls during the course of this battle. Once you've defeated the creatures, head on to your right (#2). Stop near the sand.
You will have to take part in a new type of an action sequence. Thankfully, there's nothing you should be worried about, because it's going to be very simple. There's a gauge in the lower left corner of the screen. You will have to wait for the sword icon to reach the upper field. After that, press the attack button. If you were correct, you will be rewarded with a new cut-scene (#2).
You will be able to advance to a new area of the map (#1). Be careful, though. You can't leave the main passageway, because you would have been attacked by undead creatures. Go up and then turn right. You will have to take part in a longer fighting sequence here. This is also a very good opportunity to score a combo chain (#2) that's needed for one of the side missions. Just make sure that you don't go too far to the left, because you would leave the safe area.
Head on to your right. Don't leave the main path, because you aren't allowed to walk on the sand. You will have to make a stop here (#1). Press the action key and win the action sequence. Now you will have to move to a small platform (#2). Finish the action mini-game once again. As a result, you are going to be transported to a new location.
Keep heading towards the right edge of the screen. You will have to face a small group of undead creatures here (#1). Thankfully, you won't have to worry about ending up near the sand. As a result, focus all of your attention on killing these creatures. Once they're gone, go right. You will have to wait for an icon to appear on the ground. Head on to the rope (#2).