You will meet with Asav. Start by pressing Triangle when you get the chance, the heroine will knock out the weapon from Asav's hand. This starts an unusual fist fight during which the first thing you should do is to keep pressing Circle to avoid enemy's attacks. After a few successful dodges you will be able to attack by pressing Square.
In the later parts of the fight you have to free yourself (by pressing Triangle rhythmically) and help Nadine who is also attacking Asav. The scene ends when you fall into water.
In the last part during which you are sliding down the aqueduct you should be ready to press L1 in order to catch the hook presented in the picture. Swing on the rope and jump on a new ledge. When the cut-scene ends you must follow Nadine and wait for the moment when the icon appears above her head to have the last optional conversation (5/5).
When you are in the jungle again you must complete a short climb and then head towards a big gate. Interact with the mechanism in order to open it. This launches a new cut-scene and you will complete this chapter.
After you return to the jungle, climb up and reach the fork. Head left, i.e. away from the large gate that you have used at the end of the previous chapter. As a result of that, you will reach another na photo opportunity location (4/4) shown in the above screenshot.Now, go towards the abovementioned gate and interact with the mechanism to open it. You will watch a cutscene and this chapter will end.
You can find the first treasure in this chapter right after you have taken a photo of the flamingoes. Chase them away and examine the tank where they have been. Note the largest rock close to the waterfalls. Peek behind it. The treasure is submerged in the water (the above screenshot, which may make it a bit more difficult to find it.